Performers considered for TOS roles
This is a list of performers who were considered for  roles, but ultimately did not appear in the role in the final episode or film. Performers listed here have been verified as having been considered by Star Trek personnel for a particular role on Trek in which they ultimately did not appear.

Richard Anthony 
Richard Anthony, real name Richard Dagosta, was cast for the one-line role of the Rider in the  third season episode  but never was filmed. 

Although he was listed on the  revised cast sheet for the episode, his role had been cut from the script at least five days earlier, as evidenced by May 17th script revisions. He does not appear on any of the episode call sheets or the daily production reports.

The omitted scene depicted a man (the Rider) approach the Enterprise landing party, where he cheerfully waves and states "Hi, Ike. Hi, boys. Good luck tonight," as he successfully rides his horse through the force field at Tombstone city limits. Seeing this, Kirk mimicked the jump on a horse himself and attempt to get out of town, unsuccessfully. While These Are the Voyages: TOS Season Three claims that this scene was filmed, all other surviving production documents show otherwise.

John Drew Barrymore 
 was originally contracted to play Lazarus (and ) in , but didn't show up to work when filming began on November 16, 1966. Robert Brown was cast as a last-minute replacement. The Star Trek production team filed a grievance against Barrymore with the Screen Actors Guild over this, which led to Barrymore's SAG membership being suspended, effectively barring him from finding acting work, for six months.

Herbert F. Solow and Robert H. Justman detail the incident in their book Inside Star Trek: The Real Story.

John Barrymore was a member of the noted Barrymore family of actors and was the father of actress .

Anne Baxter 
 was originally offered the role of Amanda Grayson but turned it down. Despite making multiple appearances in the  television series, Baxter later complained to the , "I don't do comic strips, and Star Trek is six or seven comic strips rolled into one." ()

Milton Berle 
 was an American comedian and actor, and one of the major television stars of the classic era. In 1967, Berle expressed his interest in appearing on Star Trek, and a script titled "He Walked Among Us" was written by Norman Spinrad as a possible vehicle for him. After a re-write by producer Gene L. Coon, Spinrad asked Gene Roddenberry to discard the script, and it went unproduced. 

Born Milton Berlinger, Berle hosted the Texaco Star Theatre, later renamed as The Milton Berle Show, between 1948 and 1956, during which he became known as America's "Uncle Miltie". After the show's cancellation, Berle appeared in numerous television and feature film roles, both as a comic and as a dramatic actor. These include 's 1963 It's a Mad Mad Mad Mad World, which also featured Madlyn Rhue, The Muppet Movie (1979, with Orson Welles, Paul Williams and Bob Baker), and Jerry Lewis' 1983 film Smorgasbord, which he co-wrote, and which was photographed by Jerry Finnerman, and featured John Abbott and Paul Lambert. On television, Berle appeared in guest roles on series such as I Dream of Jeannie, Get Smart, Mannix, The Mod Squad (starring Tige Andrews and Clarence Williams III, produced by Harve Bennett), Fantasy Island (starring Ricardo Montalban), and Murder, She Wrote (starring William Windom). He also made several appearances as "Louie the Lilac" in the 1960s Batman television series, where he appeared alongside Yvonne Craig and Julie Newmar, and stuntmen Ron Burke, Vince Deadrick, Lou Elias, Eddie Hice, Hubie Kerns, Sr., Troy Melton, Gil Perkins, George Sawaya, Roy Sickner, and Al Wyatt.

John D.F. Black 
Main article: John D.F. Black
John D.F. Black, writer, story editor and associate producer of Star Trek at the time, was asked by Gene Roddenberry to play the crippled Fleet Captain Christopher Pike in  and , because Black's blue eyes matched those of Jeffrey Hunter's (who played the healthy Pike in ). Black didn't hesitate much to turn down the offer, and the part was eventually given to Sean Kenney.  Black left the series soon afterwards mainly due to his disputes with Roddenberry.

George Bochman 
George Bochman auditioned for the role of Dave Bailey in the  episode . Bochman was listed in the Star Trek Concordance as appearing in the episode.

Lloyd Bridges 

 was an Emmy-nominated American actor who was approached by Gene Roddenberry in  to play the lead in the pilot,  for a proposed series. Bridges turned down the role, not wanting to be involved in another science fiction project following the failure of his 1950 film Rocketship X-M and feeling that doing a "space show" would hurt his career. (Star Trek - Where No One Has Gone Before, pp. 8-9;  ) Years later, Roddenberry still considered hiring Bridges, this time for the role of Gary Seven in the proposed series , and later in the backdoor pilot episode of the same title. However, Bridges again turned him down. (These Are the Voyages: TOS Season Two)

A glimpse of what Bridges might have looked like in Star Trek, had he accepted, was proffered when he later did make a noticeable appearance as a guest star in two 1978 episodes of the "space show" Battlestar Galactica (re-edited as the 1979 feature film Mission Galactica: The Cylon Attack), playing the part of the strong but misguided Commander Cain, commanding the Battlestar Pegasus. In Ronald D. Moore's 2003-2009 revamped version of the series, the character of Cain was revitalized as an admiral, but was this time cast as a female and played by Michelle Forbes.

Bridges had previously acquired fame as the star of the action/adventure series Sea Hunt. In his later career, he became known for comic roles in films such as Airplane! (1980, with Gregory Itzin, Jason Wingreen, Kenneth Tobey and Paula Moody), reprising the role in its 1982 sequel Airplane II: The Sequel. Amusingly, both the ship he was slated to command as well as his replacement, William Shatner, made appearances in the sequel. Other notable comic appearances Bridges made was in Hot Shots! (1991, with Chris Doyle, co-produced by Steven McEveety) and as a guest star in an episode of Seinfeld (with Gene Dynarski and Jason Alexander), earning him an Emmy nomination. In the early 1990s, he also starred in a short-lived series Capital News, which was photographed by Jerry Finnerman.

Gloria Calomee 
Gloria Calomee was among the original three actresses considered for the part of Lieutenant Uhura before Nichelle Nichols was cast. (These Are the Voyages: TOS Season One)

According to some sources, Calomee appeared as a background extra in the first regular episode, , however this information can be heavily disputed. It is possible that her name only appeared on call sheets because of her auditions for the role of Uhura.

Joseph Campanella 
Main article: Joseph Campanella
Joseph Campanella was almost given the role of Kang in , but then it was decided he might not be able to "draw enough fire" in the part, so Michael Ansara was cast instead. (The Star Trek Interview Book) More than three decades later, Campanella played the Arbitrator in .

James Coburn 
Academy Award-winning actor  was among the three final choices for the leading role of the captain in the first pilot, , along with Jeffrey Hunter and Patrick O'Neal. The part went to Hunter. (These Are the Voyages: TOS Season One)

Coburn was a prolific actor, best known for his roles in films such as The Magnificent Seven (1960, with Joseph Ruskin, Whit Bissell and John A. Alonzo), The Great Escape (1963), Major Dundee (1965), Our Man Flint (1966, with Peter Brocco), Pat Garrett & Billy the Kid (1973) and Cross of Iron (1977). Later he appeared in supporting roles in several movies, including The Muppet Movie (1979, with Orson Welles, Bob Baker), Young Guns II (1990), Hudson Hawk (1991), Sister Act 2: Back in the Habit (1993, starring Whoopi Goldberg), Maverick (1994), The Nutty Professor (1996) and Snow Dogs (2002, co-starring Nichelle Nichols).

Yvonne Craig 
Main article: Yvonne Craig
Yvonne Craig was one of the actresses considered for the role of Vina in , before the role went to Susan Oliver. She was considered mostly because of her professional dancing background, required for the Orion courtyard scenes. Eventually, Craig went on to guest star as Marta in , coincidentally wearing green Orion makeup.

Michael Dunn 
Main article: Michael Dunn
Michael Dunn was among the actors initially considered by Gene Roddenberry for the role of Spock for , before the part went to Leonard Nimoy. (These Are the Voyages: TOS Season Three)

Two years later, Dunn was NBC's choice for the role of Balok in , as he was a widely recognized face due to his appearances in the film Ship of Fools and the series The Wild Wild West. Roddenberry opted for someone less known and more "strange", and eventually hired 7-year-old Clint Howard for the part. Dunn was later cast as Alexander in . (These Are the Voyages: TOS Season One)

John Gabriel 
 is an actor from Niagara Falls, New York who apparently played an unnamed crewman in the  first season episode , according to the Star Trek Concordance. Presumably, he merely auditioned for a role, possibly that of Dave Bailey, and his name only appeared on call sheets because of his auditions.
 
He may be best remembered for his role as "Dr. Seneca Beaulac" in the television soap opera Ryan's Hope (1975-1985, 1988-1989), co-starring  actress Kate Mulgrew. He also had a recurring role as "Andy Rivers" on The Mary Tyler Moore Show, and appeared twice as "Dr. Dan Gifford" on The Untouchables. One of the more notable roles of his career is the one he didn't get – he was cast as the Professor in the pilot of Gilligan's Island, but when the series was picked up, the role was re-cast with Russell Johnson.

In 1958, he had a small role in the musical South Pacific, which co-starred  guest star Ray Walston and fellow TOS guest star France Nuyen. The same year, he appeared in The Young Lions, which also featured Dean Martin and Trek alumni Parley Baer, Hal Baylor, Paul Comi, Robert Ellenstein, Sam Gilman, and Michael Pataki. He also appeared in the 1966 Westerns El Dorado (with John Wayne, Paul Fix, Adam Roarke, and Victoria George) and Stagecoach (with Brad Weston, Oliver McGowan, Bruce Mars, and Hal Lynch). Other film credits include Red Line 7000 (1965, with George Takei, Marianna Hill, and Terri Garr), Oh! What a Lovely War (1969, with Maurice Roëves), and Just Tell Me What You Want (1980, with Peter Weller and John Walter Davis).

Lee Grant 
 is an American actress and director, who was casting director Joseph D'Agosta's first choice for the role of the Romulan commander in . However, Grant turned the offer down, and the part went to Joanne Linville instead. (These Are the Voyages: TOS Season Three)

Grant is most famous for appearing in such films as Valley of the Dolls (1967), In the Heat of the Night (1967), Shampoo (1975) (for which she won an Academy Award for Best Supporting Actress), and Voyage of the Damned (1976). She also appeared in 71 episodes of Peyton Place in the series' 1965-66 season, and the pilot for Columbo ("Ransom for a Dead Man"), for which she was nominated for an Emmy.

Ena Hartman 
Ena Hartman was among the original three actresses considered for the part of Lieutenant Uhura before Nichelle Nichols was cast. (These Are the Voyages: TOS Season One)

According to some sources, Hartman appeared as a background extra in the first regular episode, , however this information can be heavily disputed. It is possible that her name only appeared on call sheets because of her auditions for the role of Uhura.

James Hong 
 is a Chinese-American actor who auditioned for the role of Lieutenant Hikaru Sulu in the second Star Trek pilot, . The role was given to George Takei instead. Hong remembered going into the audition just before Takei. 

Hong has a long and prolific career in both film and television, appearing in series such as I Spy, The Bill Cosby Show, I Dream of Jeannie, The Man from U.N.C.L.E., The Streets of San Francisco, Dynasty, MacGyver, Miami Vice, and TJ Hooker (starring William Shatner, James Darren and Richard Herd), and later in J.J. Abrams' Alias, Seinfeld, Law & Order: Special Victims Unit, Bones, The Big Bang Theory, and Chuck. He also appeared in films like Robert Wise's The Sand Pebbles, Blade Runner, and the remake of The Day the Earth Stood Still. He played the villainous sorcerer Lo Pan in Big Trouble in Little China, co-starring Kim Cattrall. He is also an established voice actor and can be heard in films such as Mulan, Kung Fu Panda, and its sequel.

DeForest Kelley 
Main article: DeForest Kelley
DeForest Kelley was originally considered by Gene Roddenberry for the role of Dr. Boyce in the first pilot, . However, director Robert Butler wanted veteran actor John Hoyt for the part. (Inside Star Trek: The Real Story, pp. 37, 39) Roddenberry then offered the role of Spock to Kelley, but he turned it down. (These Are the Voyages: TOS Season One)

A year later, Roddenberry again wanted Kelley to play the ship's doctor (this time renamed Mark Piper), but again, the director, James Goldstone opted for another actor, Paul Fix. Finally, Roddenberry stood on his heels, and got Kelley to portray the doctor, named Leonard McCoy, for the series itself, starting with the first regular episode, . (Inside Star Trek: The Real Story, pp. 75, 152)

Martin Landau 
 was apparently one of the actors considered for the role of Spock, but instead opted to take the role of Rollin Hand on Mission: Impossible, which was produced by Desilu at the same time.   Leonard Nimoy went on to play Spock and, ironically, later joined the cast of Mission: Impossible after Landau left that show.

Landau stated "I can't play wooden. It's the antithesis of why I became an actor." ( #108, , p. 44) According to Landau, he "absolutely never" regretted turning down Spock, a character he viewed as "the antithesis of why I do what I do", and a contrast to , the role he instead chose, which he described as "the antithesis of Spock, a character who was everybody, all emotional levels, all colors, shapes, sizes." Landau announced, "I would make the same decision today. But I knew if the show hit, Spock would be very effective. You have to think of the turmoil of the '60s. A super-intelligent creature with pointy ears who thought logically was exactly right–except I didn't want to act it. I did not want to be saddled with the role of a character without feeling. I would have become a newscaster. Actually, newscasters are more emotional that Spock." ( #108, , p. 46)

Decades later, he echoed these sentiments, "I turned down Star Trek. It would've been torturous. I would've probably died playing that role. I mean, even the thought of it now upsets me. It was the antithesis of why I became an actor. I mean, to play a character that Lenny (Nimoy) was better suited for, frankly, a guy who speaks in a monotone who never gets excited, never has any guilt, never has any fear, or was affected on a visceral level. Who wants to do that?" (Pioneers of Television: Science Fiction)

According to Michael Kmet of TrekFactCheck, D.C. Fontana stated "From the day in 1964 that Gene Roddenberry showed me the first outline/bible for STAR TREK, Leonard Nimoy was Mr. Spock. There was never anyone else considered." In addition, Kmet stated that Landau was not named in any casting documents archived at UCLA for any role, including that of Spock. 

In addition to his Mission: Impossible role (for which he received several Emmy Award nominations), Landau is known for many film and television credits including the lead role of John Koenig in Space: 1999 (which co-starred Nick Tate and Clifton Jones, and was produced partly by Fred Freiberger), Oscar-nominated roles in Tucker: The Man and His Dream (with Christian Slater, and Dean Stockwell), and Crimes and Misdemeanors, and his Oscar-winning performance as Bela Lugosi in Ed Wood (featuring Biff Yeager, and Daniel Riordan).

Mittie Lawrence 
Mittie Lawrence was among the original three actresses considered for the part of Lieutenant Uhura before Nichelle Nichols was cast. (These Are the Voyages: TOS Season One)

According to some sources, Lawrence appeared as a background extra in the first regular episode, , however this information can be heavily disputed. It is possible that her name only appeared on call sheets because of her auditions for the role of Uhura.

Mark Lenard 
Main article: Mark Lenard
Mark Lenard was slated to play the role of the recreation of Abraham Lincoln in , but prior commitments prohibited him from taking the part. As Lenard explained it, "I was doing a series at the time called Here Come the Brides in which I played Aaron Stemple, the resident bad guy/rich man. The Lincoln segment came up about Christmas time when we had a slight hiatus, and I thought I could work it in. I had already played two roles on Star Trek and they were well received. But it turned out we just couldn't work it in. I think we went back to work on the other series too soon, and instead of having the six or seven days I would have needed to do the role, I only had three or four days." 

Lenard, of course, was best known for playing a Romulan Commander and Spock's father, Ambassador Sarek.

Jonathan Lippe 
, also known under his stage name Jonathan Lippe, auditioned for the role of Dave Bailey in the  episode . Lippe was listed in the Star Trek Concordance (p. 304) as appearing in the episode, however he himself has noted that he did not make an appearance on the series. 

His other television credits include repeated guest spots on Gunsmoke (1966-1974, with Morgan Jones and Craig Hundley). He appeared twice on Twelve O'Clock High, starring Robert Lansing; first in 1964 (with Gary Lockwood and Nancy Kovack) and then again in 1966 (with Seymour Cassel).

In 1967, he appeared on Wild Wild West with Joseph Campanella and The Invaders with Phillip Pine, Dallas Mitchell, Bill Erwin, William Sargent and Frank Overton. In 1970, he appeared on The High Chaparral with Henry Darrow and Tony Epper and  (with Leonard Nimoy, Mark Lenard, and Arthur Batanides). He also made three appearances on Petrocelli (1975-1976), with William Windom.

In 1968, he appeared in the classic Western Hang 'Em High, along with Mark Lenard, Bill Zuckert, Ned Romero, and Paul Sorensen. That same year, he appeared in Ice Station Zebra, co-starring Lloyd Haynes, Ernest Borgnine, Joseph Bernard, William O'Connell, Michael Rougas, Buddy Garion, Gary Downey, and Jim Goodwin). His other film credits also include One is a Lonely Number (1972, with Monte Markham and Mark Bramhall) and the low budget thriller Blood Voyage (1976, with Pete Kellett).

He also appeared the TV movies Shadow on the Land (1968, with Paul Sorensen), The New Healers (1972, with William Windom and Robert Foxworth), and A Case of Rape (1974, with Ronny Cox, Cliff Potts, Patricia Smith, Charles Macaulay, Alex Henteloff, and Davis Roberts). In 1976, he appeared in the acclaimed Helter Skelter with Marc Alaimo, Robert Ito, Skip Homeier, Bruce French, Rod Arrants, Paul Kent, Alan Oppenheimer, Phillip Richard Allen, David Clennon, and Roy Jenson. And in 1977, he was in Bunco (with Meg Wyllie and Kenneth Mars) and Green Eyes (with Paul Winfield and Robert DoQui).

Lippe was the first actor to play "The Most Interesting Man in the World" in the ad campaign for Dos Equis beer from 2007 to 2015. Lippe's character was heralded at being exceptional at all things. His character was replaced by another actor, Augustin Legrand, in September 2016.

Jack Lord 

 was an American actor who was Roddenberry's first choice for the role of Captain James T. Kirk in  after Jeffrey Hunter refused to reprise his role of Christopher Pike for the second pilot, . A deal with Lord fell through when Lord demanded fifty percent ownership of the show.   The role subsequently went to William Shatner. (Star Trek - Where No One Has Gone Before, pp. 8-9)

Lord is best known for starring as Detective Steve McGarrett on the hit series Hawaii Five-O, which enjoyed a twelve-year run from 1968 to 1980 (Lord retired from acting after its cancellation). He is also known to James Bond fans for playing Felix Leiter in the first Bond film, Dr. No.

Bruce Mars 
Main article: Bruce Mars
Bruce Mars was one of the actors considered for the role of Lieutenant Dave Bailey in , before the part went to Anthony Call. Mars later appeared as  in  and as Charley in . (These Are the Voyages: TOS Season One) Some sources list Mars as appearing in "The Corbomite Maneuver" as an extra, but he is not seen in the finished episode. Probably his name remained on the cast lists because of him being in competition for the part of Bailey.

Arlene Martel 
Main article: Arlene Martel
Arlene Martel was originally considered for the role of Dr. Dehner in . The role would have required her to wear silver contact lenses, which might have damaged her sensitive eyes. Sally Kellerman was cast instead. 

Nearly two years later, Martel auditioned for the role of  in . She was not cast in the role, because the production staff saw her as an ideal candidate for T'Pring in the upcoming episode, .

Roddy McDowall

Stewart Moss 
Main article: Stewart Moss
Stewart Moss was one of the actors considered for the role of Lieutenant Dave Bailey in  before Anthony Call got the part. Moss, a friend of casting director Joseph D'Agosta, later appeared as Joe Tormolen in  and Hanar in . (These Are the Voyages: TOS Season One) Some sources list Moss as appearing as an extra in "The Corbomite Maneuver", but he is not seen in the episode. This is likely due to the fact that his name appeared on cast lists as a candidate for the Bailey role.

Patrick O'Neal 
 was among the final three actors considered for the leading role of the captain in the first pilot, . Eventually, Jeffrey Hunter won the part. (These Are the Voyages: TOS Season One)

Later, Roddenberry considered O'Neal for the role of Gary Seven for , however the part went to Robert Lansing. (These Are the Voyages: TOS Season Two)

O'Neal was best known for the 1973 film, The Way We Were, which also featured Diana Ewing, Don Keefer and Roy Jenson. He also appeared in films as The Kremlin Letter (1970), The Stepford Wives (1975), Like Father Like Son (1987) and Under Siege (1992). On television, he guest starred among others, in The Twilight Zone, Route 66, Barnaby Jones (co-starring Lee Meriwether), The Streets of San Francisco, Columbo, Murder, She Wrote (co-starring William Windom) and A Man Called Hawk, which starred Avery Brooks. In 1957-58 he starred in the short-lived sitcom Dick and the Duchess.

David Opatoshu 
Main article: David Opatoshu
David Opatoshu was considered by Gene Roddenberry for the role of Doctor Phil Boyce in the first Star Trek pilot, , before the role finally went to John Hoyt. Opatoshu appeared in a guest role as Anan 7 in .

Gregg Palmer 
Gregg Palmer was originally cast for the role of the Rancher in the  third season episode . He was named on the  revised cast sheet for the episode, along with the scrapped role of the Rider, played by Richard Anthony. Both roles were omitted from the script last minute before filming, and neither actor appeared on the call sheets or the daily production reports. 

Between 1950 and 1982, Palmer (birth name Palmer Lee) had roles in various TV programs such as The Lone Ranger, Gunsmoke (twenty episodes), Bonanza (five episodes), Rawhide, Tarzan (three episodes), Mission: Impossible, Jason King, Alias Smith and Jones, and Quincy, M.E. His film roles include Chisum, The McKenzie Break, and The Shootist.

He was long thought to be an actor of the same name who worked in Doctor Who, but this was thoroughly debunked in the 2013 DVD release of The Tenth Planet. 

Palmer passed away on 31 October 2015, in Encino, California. His wife, Ruth Palmer died in 1999. He attended the Golden Boot Awards but did not win the award himself.

Michael J. Pollard 
Main article: Michael J. Pollard
Michael J. Pollard was Gene Roddenberry's original choice for the role of Charles Evans in , as Roddenberry "had been hearing good things about him". Casting director Joseph D'Agosta opted for Robert Walker instead, who finally got the part. However, D'Agosta remembered Pollard and later cast him as Jahn in .

Gregory Reese 
An actor identified on the call sheets as Gregory Reese and Gregory Reece had been originally cast as Morgan Earp in , however, he was removed from the episode after the first filming day, due to his drug problems. Rex Holman, who was originally cast as Virgil Earp, replaced him in the role, and Charles Maxwell was hired to play Virgil instead. (These Are the Voyages: TOS Season Three, pp. 72-73) 

It can be assumed that the actor in question was , who appeared in a guest role on the series "N.Y.P.D." in 1967, and in the film Shaft's Big Score! in 1972.

Cindy Robbins 

 is a former actress, who was the runner-up for the role of Yeoman J.M. Colt in the first Star Trek pilot, . She was given a costume / makeup test with Leonard Nimoy, however, Laurel Goodwin was eventually chosen for the part.

Robert Ryan 
 was the American actor whom writer Norman Spinrad envisioned for the role of Commodore Matt Decker in . Ryan was approached for the role, but he was unavailable due to other commitments. William Windom was given the part, instead, and Spinrad has expressed disappointment that Ryan was not cast. 

Ryan was nominated for an Academy Award for his performance in the 1947 film Crossfire. He also received a BAFTA award nomination for his starring role in the 1962 film Billy Budd, which co-starred John Neville. He has also starred in such acclaimed films as The Set-Up (directed by Robert Wise), Clash by Night (co-starring Keith Andes), Bad Day at Black Rock, and The Professionals. He starred opposite Jeffrey Hunter in the 1956 Western The Proud Ones. He also appeared as John the Baptist in the 1961 film King of Kings, again opposite Jeffrey Hunter. Ryan and Hunter worked together a third time as part of the Oscar-winning ensemble World War II film, The Longest Day.

Perhaps Ryan's best-known film role is that of Deke in 's 1969 action western, The Wild Bunch. Four years after this film's release, Ryan died of lung cancer at the age of 63. His last film, 's 1973 drama The Iceman Cometh, earned Ryan posthumous awards from the National Board of Review and the National Society of Film Critics Awards.

Malachi Throne 
Main article: Malachi Throne
Malachi Throne was considered at one point by Gene Roddenberry for the role of the ship's doctor, Phil Boyce in . However, Throne turned the offer down, saying he did not want to play "the third man" next to the hero and his sidekick. Throne opted to play Spock, but that role was already given to Leonard Nimoy. Roddenberry then offered Throne the chance to provide The Keeper's voice, which he did. (These Are the Voyages: TOS Season One)

Later Throne played Commodore José Mendez in  and  and Senator Pardek in  and .

Beau Vandenecker
 was tapped to play the uncredited stunt role of "Stunt ()" in the episode , as his name appears on the cast sheet, dated . The role, however, was ultimately filled by regular series stuntman Robert Herron.

Jon Voight 
 is an Academy Award-winning American actor, who was originally considered for the role of Apollo in , but was hired for another project. 

Voight came to prominence two years later with his role in the Oscar-winning drama Midnight Cowboy. He later appeared in films such as Catch 22 (1970), Deliverance (1972, co-starring Ronny Cox), Coming Home (1978) for which he won an Academy Award, The Champ (1979), Runaway Train (1985), Heat (1995), Mission: Impossible (1996), Anaconda (1997), U Turn (1997), Enemy of the State (1998), Pearl Harbor (2001), Ali (2001, with LeVar Burton), The Manchurian Candidate (2004, with Dean Stockwell), National Treasure (2004, with Christopher Plummer), Transformers (2007, with Glenn Morshower) and several other projects. Voight is also the father of actress  with whom he appeared in Lara Croft: Tomb Raider (2001) and its sequel.

Jessica Walter 
 was an American actress who was approached to play Miranda Jones in . She was unavailable, and the role went to Diana Muldaur. 

In the same year, Walter appeared in an episode of The Name of the Game, helmed by the "Is There in Truth No Beauty?" director, Ralph Senensky, which also featured David Opatoshu, Don Keefer, Lloyd Kino, and Jason Wingreen.

She is best known for appearing alongside  in his directorial debut, Play Misty for Me (1971) and for playing the role of Lucille Bluth in the sitcom Arrested Development (2003-2006). She guest-starred in "Mind Over Mayhem", a 1974 episode of Columbo alongside Lou Wagner, Robert Walker, Arthur Batanides, and Charles Macaulay. In 1965, she co-starred with William Shatner in the short-lived television series, For the People. She also appeared as a regular in the first season of 90210 in 2008. Recently she starred in the  sitcom Retired at 35.

Since 2009, she had voiced the character of spymaster Malory Archer on the popular FX adult animated series Archer.

Dawn Wells 
 was an American actress and comedienne, most famous for her role as Mary Ann Summers in the popular sitcom . Along with Terri Garr, Wells was considered for the part of Roberta Lincoln in  (and the proposed spin-off series of the same title). Despite Wells being much more well-known than Garr at the time, Gene Roddenberry eventually chose Garr because she looked "weird" and fit the part better. (These Are the Voyages: TOS Season Two, p. 591)

Brad Weston 
Main article: Brad Weston
After playing the role of Ed Appel in , Brad Weston was briefly considered by Gene Roddenberry for the then-unspecified part of a young male crewmember, hired to attract the teen-aged female audience, as a regular from the second season. The character eventually evolved into Ensign Pavel Chekov, played by Walter Koenig. (These Are the Voyages: TOS Season One, p. 487)

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