Ron Palillo, best known for his role as Arnold Horshack on the 1970s TV sitcom "Welcome Back, Kotter," has died, the Palm Beach Post reports. He was 63.

He died at 4:30 a.m. at his Palm Beach Gardens home, a friend, Stacy Sacco, told the paper [5].

Palillo had been teaching at the G-Star Academy, a Florida charter school. He previously taught at his alma mater, the University of Connecticut, according to Corporate Artists [6], which employed him for speaking gigs.

Also read: 'Welcome Back, Kotter' Star Robert Hegyes Dies at 60 [7]

Palillo played the goofy Horshack from 1975 to 1979 on "Kotter," which starred Gabe Kaplan as a hip but beleaguered teacher who presided over a classroom that also included a young John Travolta.

Palillo said he came up with Horshack's trademark, an overly excited "Ooh ooh!"

He continued to work steadily after "Kotter," guest starring on shows including "The Love Boat," "The A-Team," and "CHiPs." He also did voice work for cartoons, including "Darkwing Duck," and played himself in several episodes of "Ellen."

Palillo was also a pen-and-ink artist who worked under his full name, Ronald G. Palillo. He said he used it as a tribute to his father.