Actor J.T. Walsh, who played Jack Nicholson’s suicidal lieutenant colonel in “A Few Good Men” and more recently starred as the villain in “Breakdown,” died Feb. 27 in La Mesa, Calif. He was 54.

Walsh died of a heart attack at Grossmont Hospital after falling ill at a San Diego-area resort hotel, said his publicist, Cynthia Snyder.

“He was just on holiday,” she said. “The paramedics came and weren’t able to revive him and took him to the hospital, where he was pronounced deceased.”

Walsh, who was born in San Francisco, did not become a full-time actor until he was 31. He had worked as an encyclopedia salesman, junior high school teacher, social worker and reporter.

As a child, Walsh was a student at a Jesuit boarding school in Ireland.

A graduate of the University of Rhode Island, Walsh became known for portraying ethically challenged men, such as Lt. Col. Matthew Markinson in 1992’s “A Few Good Men” and Sgt. Major Dickerson in 1987’s “Good Morning, Vietnam.”

Walsh, who lived in Los Angeles with his son, TV production assistant John West, most recently appeared in “Breakdown,” playing bad guy Red Barr opposite Kurt Russell.

In 1996, he portrayed mental patient Charles Bushman in Billy Bob Thornton’s acclaimed “Sling Blade.”

Walsh recently completed work on New Line’s “Pleasantville” with Jeff Daniels and Joan Allen, and New Regency’s “The Negotiator” with Samuel L. Jackson.

Walsh, who had been active in community theater, was discovered by a director in 1974 and began working in Off Broadway shows. He met playwright David Mamet in 1976 and won a role in the first performance of “American Buffalo.”

His big break came when he was cast in another Mamet play, “Glengarry Glen Ross,” on Broadway in 1984. The role brought him to the attention of Hollywood casting agents, and he moved to Los Angeles four years later.

Walsh, who was an avid reader and spoke fluent German, is survived by his son, brother Christopher Walsh and sisters Patricia and Mary Walsh.

Services were scheduled for 5 p.m. Tuesday at the Old North Church at Forest Lawn Memorial Park in Hollywood Hills.