Nicky Katt, an actor known for playing wild cards and tough guys on TV shows like “Boston Public” and in films like “Boiler Room” and “Dazed and Confused,” has died. He was 54.

His death was confirmed by his lawyer, John Sloss, who did not provide any further details.

Mr. Katt began his career as a child actor and later became a character actor specializing in unsympathetic henchmen, working with acclaimed directors like Richard Linklater, Christopher Nolan and Steven Soderbergh.

Mr. Katt was regularly cast as a pushy, temperamental man whose virtues, if any, were not immediately self-evident.

In “Dazed and Confused,” he is a nerd-shoving high school taunter who grits his teeth while pummeling a fellow teen. “I only came here to do two things, man: kick some ass and drink some beer,” Mr. Katt, as Clint Bruno, said with cocky bravado. “Looks like we’re almost out of beer.”

In “Boston Public” (Fox, 2000-2004), a show about an urban high school, Mr. Katt played Harry Senate, a geology teacher and charismatic rule breaker who brings his class to attention by firing blanks out of a pistol, but who also successfully disarms a student threatening another teacher with a gun.

In a 2002 interview with The Los Angeles Times, Mr. Soderbergh described Mr. Katt’s performances as “dangerously out of control” but rigorously studied.

“He’s absolutely fearless,” Mr. Soderbergh said. “No idea is too outrageous. He’ll try anything.”

Nicky Katt was born in May 1970 in South Dakota. He appeared on several TV shows, including “Fantasy Island” and “CHiPs,” as a preteen.

Complete information about his family and survivors was not immediately available.

Talking to The Los Angeles Times, Mr. Katt said he found most actors to be either desperate or frustrated. To cope with the vagaries of the profession, Mr. Katt amassed a wide repertoire of quotes and anecdotes from celebrated figures of the past.

One piece of advice: “You should never name-drop,” he said. “De Niro told me that.”