Ron Palillo, best known for his role as Horshack, the wise-cracking student on ’70s sitcom “Welcome Back, Kotter,” died suddenly from a heart attack near his Palm Beach, Fla. home, according to reports. He was 63.

Although he played a student assigned to a class for slow learners, known as the “Sweathogs,” Palillo was graduate of the University of Connecticut and taught classes there during the 1990s. He was also an accomplished artist. He illustrated several children’s books.

He had a signature line on the show, “Ooh ooh ooh, Mr. Kotter,” and co-starred with John Travolta, who played Sweathog Vinnie Barbarino.

His television role, which ran from 1975 to 1979, was probably his highest profile acting job, but he kept busy after the series with parts in several movies.

He also acted on Broadway. He appeared as Mozart in Amadeus, George in Who’s Afraid of Virginia Woolf?, and Nathan Detroit in Guys and Dolls. He also appeared in The Curse of Micah Rood. His Broadway stint included 2008’s Broadway Backwards 4, a charity event for people afflicted by AIDS.

Palillo’s long-time partner, Joseph Gramm, reported found Palillo unconscious and unresponsive. An ambulance rushed him to the hospital, where he was pronounced dead on arrival, according to gossip site TMZ.

His heart attack was sudden and unexpected, although Palillo had been a heavy smoker for years, which is known to contribute to heart disease.

He was teaching at the G-Star School of the Arts, and appeared to be in good health when he was last seen there.