Nicky Katt, who played teacher Harry Senate on “Boston Public” after starting as a child actor and going on to play an assortment of tough guys in movies including “Dazed and Confused” and “Boiler Room,” has died. He was 54.

His death was reported by his friends and by attorney John Sloss, and reportedly occurred on April 8 in Burbank.

Often playing heavies and villains, Katt worked with Richard Linklater, appearing in “Waking Life,” “SubUrbia” and “School of Rock.” For director Steven Soderbergh, he appeared in “The Limey” as Stacy the Hitman, as Hitler in “Full Frontal,” and had one of his final roles in “Behind the Candelabra.” Christopher Nolan cast him in “Insomnia” and “The Dark Knight,” in which he played a S.W.A.T. team member.

On “Boston Public,” Katt played the popular geology teacher Harry Senate, who taught troublemaker kinds in “the dungeon.” David E. Kelley arranged for him to be written out of the show after suffering a mental breakdown so Katt could pursue his movie career after three seasons.

In Linklater’s “Dazed and Confused,” Katt played the tough guy Clint Bruno, who threatens Mike (Adam Goldberg) and then beats him up. He went on to appear in Gregg Araki’s “Doom Generation,” Kathryn Bigelow’s “Strange Days,” in Neil Jordan’s “The Brave One” and in two Joel Schumacher movies, “A Time to Kill” and “Batman & Robin.”

Katt was memorable in Christopher McQuarrie’s directorial debut, the 2000 Western action film “The Way of the Gun,” as a bodyguard who gets injured in a shootout.

He also provided the voice of Atton Rand for the “Star Wars: Knights of the Old Republic II – The Sith Lords” video game.

Katt, who lived part time in Austin, Texas, worked with Richard Rodriguez on “Sin City.” He also appeared in Tarantino’s “Death Proof.”

In a 2008 interview about his role in David Gordon Green’s “Snow Angels,” he told Todd Gilchrist, “I kind of am notorious for bringing a lot of humor to stuff, and not in a scene-stealing way, [but] especially if something is really kind of heavy subject matter I’m kind of like oxygen for a drowning man.”

“I mean, everyone also says that the bad guys are the most fun, but I’ve definitely gone through streaks where that’s all that people wanted me to play, the bad guy, especially after ‘Dazed and Confused.’ But I’ve been really lucky because I get to play all different types of guys,” he said.

Born in South Dakota, Katt started out as a child actor on TV and with small roles in “Gremlins” and “The ‘Burbs.”

On television, he appeared on shows including a recurring role on the “Herbie, the Love Bug” series, “V,” “Quincy M.E.,” “Father Murphy” and “Law and Order.” His last credited appearance was on the series “Casual” in 2018.