In the 1980s and 1990s, Cullen appeared on a number of television shows. He has played Coran, Stride the Tiger Fighter, and King Alfor in the Lion "Voltron" series, the transforming spaceship/robot Ramrod, the heroic Commander Eagle and the villainous Nemesis in the 1980s anime series "Saber Rider and the Star Sheriffs", Commander James Hawkins in the Vehicle "Voltron" series, Eeyore in the "Winnie the Pooh" franchise, Original First Voice of KARR in "Knight Rider", Antor and Bomba, and Gunner, in "Dino-Riders", Airbourne, Nemesis Enforcer and Zandar in ', He played Mantor/Mantys in Coleco's 5 episode mini-series "Sectaurs" in 1986; Red Skull in the 1981 cartoon series of "Spider-Man", Klaar and Zanzoar in "Megas XLR" and Mantus in "The Pirates of Dark Water". He also had a voice part in the 1984 motion picture "Gremlins" (as a gremlin) and in the first season of the 2008 "Knight Rider" series, where he reprised his vocal role as KARR (from the original "Knight Rider" series). He also did voicework in ' series, notably as Japheth, one of Noah's sons in the "Noah's Ark" episode, and the King of Nineveh in the "Jonah" episode. He was well known by some as the main villain Venger in the animated series of "Dungeons and Dragons". He played the evil sorcerer Renwick in the lesser known series "Little Wizards" and played Cindarr in the short-lived series "".