Lance has starred on some TV shows and in TV movies, his best known TV role was in the 1980s hit series The A-Team as Colonel Roderick Decker, a U.S. Army Colonel who tried to catch the fugitive Vietnam Vets. Lance played the role of Col. Decker from 1983-1986. He also had a recurring role in the other 1980s hit TV series Magnum, P.I. as a colonel, Colonel 'Buck' Greene. Lance's other shows include the short lived series Werewolf in 1987. In 1980, he starred with Kenny Rogers in the TV movie The Gambler. Lance also appeared in the other hit 1980s hit TV series Knight Rider in the pilot episode "Knight of the Phoenix" and appeared (as a different character) in the season 2 episode "Knight In Shining Armor"; and also played three different characters in Airwolf (in To Snare A Wolf, Sweet Britches and Wildfire). Lance also starred on the hit 1980s TV series Dallas as Al Halliday in 1989.
He has made many guest appearances on TV shows, his appearances range from "Rockford Files (A Deadly Maze)", Gunsmoke, Barbary Coast, Logan's Run, Battlestar Galactica, Buck Rogers in the 25th Century, The Dukes Of Hazzard, Airwolf, Voyagers!, Knight Rider, MacGyver, Star Trek: The Next Generation as a Klingon in the season 2 episode "The Emissary".
Mr. LeGault also did a stint in the video game world appearing as the voice of Major Manson in the 1998 hit game Battlezone II: Combat Commander.
On the Knight Rider Season one DVD Pilot Commentary, creator Glen Larson mentioned that Lance LeGault had "a voice that was four octaves lower than God's." In truth, LeGault does indeed have a characteristically low voice, if not gravely; this trait helped him fetch roles (often) as a villain or other "tough guy." It also resulted in a side career doing voiceover work. LeGault's trademark voice was at one point featured on self-guided tour cassettes at Elvis Presley's Graceland in Memphis, Tennessee.
LeGault also appeared in Elvis Presley's groundbreaking NBC Television special of 1968 'Elvis' (aka The 68 Comeback Special) where he sat at the side of the stage playing a tambourine.