Ronald Gabriel "Ron" Palillo (April 2, 1949 – August 14, 2012) was an American television and movie actor, who is best known for his role as high school student Arnold Dingfelder Horshack on the ABC sitcom Welcome Back, Kotter, from 1975 to 1979.
Palillo was born in Cheshire, Connecticut on April 2, 1949. He was educated at University of Connecticut. Palillo died on August 14, 2012 from a heart attack in his Palm Beach, Florida home. He was 63 years old. He is survived by his partner of 41 years, Joseph Gramm.