Gilyard’s acting career spanned more than three decades, having started in the late 70s. His major film roles in the 80s include Sundown in Tom Cruise's Top Gun (1986) and Theo in Bruce Willis' Diehard (1988), the computer whiz of the villain group headed by Hans Gruber (Alan Rickman).
Gilyard is another member of the original Diehard antagonist crew to pass away, succeeding Rickman, who died in 2016 and Alexander Godunov, who died in 1995.
More of the actor’s film credits include The Perfect Race (2019), Christmas on the Coast (2018), The Sector (2016), The Beast (2016), The Track (2016), A Matter of Faith (2014), From Above (2013), Little Monsters & Left Behind: The Movie (2000), Left Behind II: Tribulation Force (2002) and Karate Kid: Part III (1986).
He also had recurring and guest-starring roles in the 1980s TV shows Diff’rent Strokes, The Fact of Life, 227, Simon & Simon, Riptide and the sixth season of CHiPS.
He was recognized for starring in the 1990s action series Walker, Texas Ranger alongside Chuck Norris and the legal drama Matlock alongside Andy Griffith.