Clarence Gilyard, who has died after a long illness aged 66, was a popular supporting actor who made his name in two of the biggest films of the 1980s: Top Gun, in which he played Marcus “Sundown” Williams, a radar intercept officer, and Die Hard, in which he was Theo, a wisecracking terrorist computer hacker – and the film’s only surviving villain.

Clean-cut and good-looking, Gilyard starred on television in NBC’s 1980s legal drama series Matlock as Conrad McMasters, a deputy sheriff who helps attorney Ben Matlock (Andy Griffith) investigate crimes. In the CBS modern-day Western series, Walker, Texas Ranger (1993-2000), he was the earnest lawman James Trivette.

Gilyard spent much of his time from the 1990s teaching acting at the University of Nevada, Las Vegas, but he continued to act and was reportedly working on a television film entitled Eleanor’s Bench and the movie The Driver at the time of his death.

Clarence Alfred Gilyard was born at Moses Lake, Washington state, on Christmas Eve 1955, the second of six children of an officer in the US air force. During Clarence’s childhood the family moved between various air force bases around the US.

From Eisenhower High School, Rialto, California, he spent a year as an Air Force Academy cadet, then attended Sterling College, an evangelical Christian college in Kansas, where he played on the football team and became interested in drama. He dropped out and enrolled at California State University, Long Beach, to study acting. Much later he did a masters in theatre performance at Southern Methodist University.

Gilyard began his career in a California children’s theatre, recalling that “we not only performed, we served the cake at birthday parties and cleaned up the mess.”

His first television role was as a student with one line on the NBC sitcom Diff’rent Strokes. Then came a regular role as Officer Benjamin Webster on the last season of the American crime drama television series CHiPS. He also had a role in the short-lived Jim Carrey sitcom The Duck Factory, though he admitted that his comedy skills fell short of what was required: “While I was doing that comedy, I was not funny. When we were reading through the script, people would laugh, laugh, laugh. Then we’d get to my line... They said, ‘Yeah, we want to use him, but he’s trying too hard’.”

Top Gun (1986), the blockbuster hit about fighter pilots that made Tom Cruise a star, marked Gilyard’s debut on the big screen and featured a much-quoted sequence after Cruise’s character “Maverick” decides not to “shoot down” the Instructor Jester during a training exercise:

“Sundown : Hey, man, we could have had him. Hey, we could have had him, man!

“Maverick: I will fire when I am goddamn good and ready! You got that?”

Gilyard’s other film credits included The Karate Kid II, Off the Mark, Left Behind: The Movie and Left Behind II: Tribulation Force. In Die Hard (1988) his most memorable scene was the one in which the criminal mastermind Hans Gruber (Alan Rickman) expresses doubt about whether Gilyard’s character Theo can crack the code to a vault containing $640 million in bearer bonds: “You didn’t bring me along for my charming personality,” Theo responds drily.

His final film credit was playing an athletics coach in The Perfect Race (2019).

Gilyard did much work for charity, serving as chairman and spokesman for Cowboys for Kids, which raises money for disadvantaged children in Arizona. Brought up as a Lutheran, he converted to Roman Catholicism in the 1990s.

Gilyard’s first marriage, to Catherine Dutko, with whom he had two children, was dissolved. He is survived by his second wife, Elena Castillo, with whom he had three children.

Clarence Gilyard, born December 24 1955, died November 28 2022