Sandy Baron was an American actor (1937-2001). Baron played Jack Klompus in Seinfeld and appeared in films such as Broadway Danny Rose with Woody Allen, Leprechaun 2, The Grifters, The Out-of-Towners, and Vamp. He regularly performed stand-up comedy routines at Catskill Mountains resorts during the 1950s. Baron also released the single Little Miss Heartbreaker, which was one of his most popular songs.