Story highlights Palillo played Arnold Horshack on "Welcome Back, Kotter"

He died of a heart attack in Florida at age 63, his agent said

He had been teaching acting to high school students

Actor Ron Palillo, who played class clown Arnold Horshack on the 1970s television comedy "Welcome Back, Kotter," has died at age 63, his agent said Tuesday.

Palillo died of a heart attack in the Palm Beach Gardens, Florida, area, where he had moved to live near his mother and was active in the theater, his agent, Scott Stander, told CNN.

He was best known for his role as one of the "Sweathogs" -- remedial students at a Brooklyn high school -- on the 1975-79 show, which starred Gabe Kaplan and launched the career of fellow Sweathog John Travolta. Palillo's "Oooh! Oooh!" appeals for attention became the character's catchphrase.

Stander called Palillo "upbeat, fun, a great friend who loved theater, loved the fans and had a great sense of humor." He taught acting to high school students at the G-Star School of the Arts, a charter school in West Palm Beach, Stander said.

Palillo made numerous guest appearances on television in the following decades, including playing himself in three episodes of the Ellen DeGeneres comedy "Ellen" in 1996. He also appeared on the reality show "Celebrity Boxing" in 2002, losing by a TKO to former "Saved by the Bell" actor Dustin Diamond.