WEST PALM BEACH, Fla. (AP) — Ron Palillo, the actor best known as the nerdy high school student Arnold Horshack on the 1970s sitcom “Welcome Back, Kotter,” died Tuesday in Palm Beach Gardens, Fla. He was 63.

Palillo suffered an apparent heart attack at his home about 4 a.m., said Karen Poindexter, a close friend of the actor. He was pronounced dead at Palm Beach Gardens Medical Center.

Palillo was inextricably linked with the character he played from 1975 to 1979 on “Kotter,” the hit ABC sitcom, in which title character Gabe Kotter returns to his Brooklyn alma mater to teach a group of loveable wiseguys known as the Sweathogs. Horshack was the nasally teen who yelped, “Oooh, ooh,” and shot his hand skyward whenever Kotter posed a question.

The show was a ratings success and pop cultural phenomenon, injecting smart-Alec phrases such as “Up your nose with a rubber hose” into the mainstream and propelling costar John Travolta to stardom. But the series only lasted as long as a high school education and its end, for Palillo, brought difficulty.

He said he felt exiled throughout the 1980s, unable to find parts, sinking into depression, and rarely venturing from his apartment. When offers did come, he felt typecast as Horshack.

“While I loved him, I really loved him, I didn’t want to do him forever,” he told the Birmingham News in 1994.

Ronald Paolillo was born April 2, 1949, in Cheshire, Conn., eventually dropping the first “o” from his surname. His father died of lung cancer when he was 10 and he developed a stutter. His mother thought getting him involved in a local theater might help. He fell in love with the stage and overcame his speech impediment.

He attended the University of Connecticut and earned parts in Shakespearean productions before his big break.

He told interviewers that his dying father’s voice inspired Horshack’s trademark wheezing laugh.

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