United States military personnel
The following is a list of United States military personnel:

Named 
 John Christopher (, United States Air Force)
 Shaun Geoffrey Christopher (Colonel)
 George Armstrong Custer (Lieutenant colonel, United States Army)
 Denning (Lieutenant general, United States Army Air Forces)
 Fellini (Lieutenant colonel, US Air Force)
 Garland (Nurse, US Army Air Forces)
 Ulysses S. Grant (General, Union Army)
 M. March (Colonel, US Air Force)
 Douglas MacArthur (General, US Army)
 Stephen G. Richey (Colonel, US Air Force)
 Thaddius "Old Iron Boots" Riker (Colonel, Union Army)
 Benny Russell (US Navy)
 Quinn (Second lieutenant, Union Army)
 Rogerson (Commander, US Navy)
 Norman Schwarzkopf (General, US Army)
 William T. Sherman (Lieutenant general, Union Army)
 Wainwright (Captain, US Army Air Forces)
  (Technician, US Air Force)
 Chuck Yeager (US Air Force)

Unnamed armed forces personnel

Air Force

Captain 

This Air Force  was stationed at an Air Force Base in 1969. 

That year he was on duty when RADAR Technician  detected a blip, registered by the sudden appearance of the  over the Omaha installation. The captain telephoned Air Defense Command to report the sighting of what was determined to be a UFO. ()

Air Police Sergeant 

The Air Police Sergeant was a staff sergeant stationed at the US 498th Airbase Group in Omaha, Nebraska in 1969. 

He was on patrol of the facility when he discovered Kirk and Sulu who had entered the base to retrieve the hard evidence of their presence, including video recordings. Upon their discovery, the sergeant took their equipment, inadvertently activating the emergency signal. Spock immediately beamed the source of the beacon – the sergeant – to the Enterprise, further endangering the timeline and complicating the mission. Aboard ship, the sergeant was clearly overwhelmed by what he saw around him, and never left the transporter room. A helpful Kyle even served him chicken soup there.

The sergeant was returned to his proper time and place during the slingshot effect experiment that returned the Enterprise to its proper time and place, effectively erasing the history in which he visited the ship. ()

Air Policeman #1 

This air policeman, ranked airman basic, accompanied Colonel Fellini when Kirk and Sulu inadvertently triggered a silent alarm while retrieving tapes so that there would be no record of the Enterprise traveling back in time. 
Kirk, who was captured while allowing Sulu to escape, was later rescued by Spock, who arrived and overpowered Fellini and the airman, the latter of which was subjected to a Vulcan neck pinch. ()

Air Policeman #2 

This air policeman, who was ranked airman basic, also accompanied Colonel Fellini to check the silent alarm during Kirk and Sulu's break-in. ()

Air Policeman #3 

This air policeman, with the rank of airman basic, stood as a guard outside Colonel Fellini's office, while he was interrogating Kirk. He greeted Captain John Christopher when he approached the door, before Sulu knocked him unconscious. ()

US 498th Airbase personnel 

US 498th Airbase personnel at the hangar and tarmac when  John Christopher intercepted the  over the US 498th Airbase Group in Omaha, Nebraska in 1969. ()

Army

Confederate soldiers  

These Confederate Army cavalry soldiers were fighting in the American Civil War, sometime between 1861 and 1865. They were seen attacking an Union Army artillery position in the time stream by Captain Archer and Daniels in 2154. ()

Corporal

MPs 
These MPs were stationed at the United States Army Air Forces base including Hangar 18 on Earth in 1947. The first MP guarded the Ferengi Quark, Rom, and Nog inside the viewing room and was knocked unconscious by Odo. The other two guards accompanied General Denning when they stopped Garland, Jeff, and the Ferengi outside of the building but were also knocked out by Odo. ()

MP guards 
MP guards stood watch outside the building Quark, Rom, and Nog were held in. ()

US Army Air Forces major 

A US Army Air Forces major was present when several men and women in US military uniforms stood on the other side of a two-way mirror in a lab, watching Quark, Rom, and Nog who had gone back in time and crashed near Roswell in 1947. ()

Union soldiers 1  

These Union infantry soldiers were fighting in the American Civil War, sometime between 1861 and 1865. They were viewed by the  landing party in 2267 via the Guardian of Forever. ()

Union soldiers 2  

These Union artillery soldiers were also fighting in the American Civil War, being attacked by Confederate Army cavalry, sometime between 1861 and 1865. They were seen in the time stream by Captain Jonathan Archer and  in 2154. ()

World War I soldiers 

These soldiers were fighting in World War I, somewhere between 1914 and 1918. They were seen in the time stream by Captain Jonathan Archer and Daniels in 2154. ()

Navy

Enterprise crew

Officer

Travers' husband 
In an alternate timeline created by the Temporal Cold War, Mr. Travers served aboard a destroyer in the Pacific Ocean during . He was married to Alicia Travers, who was a resistance fighter for the American Resistance in New York City. ()

Earth personnel
 United States armed forces personnel
Unnamed Humans