A performer by the age of three, Barty appeared in numerous "Mickey McGuire" shorts of the late 1920s and early '30s, playing the younger brother of child-star Mickey Rooney. He acted in many films of the 1930s, including the Busby Berkeley musicals Gold Diggers of 1933 and Footlight Parade, the Shakespeare adaptation A Midsummer Night's Dream, and William A. Wellman's comedy Nothing Sacred. Barty stopped growing at the height of 3'9" and has been a lifelong activist for the rights of little people, founding Little People of America in 1957 and the Billy Barty Foundation in 1975. His notable later films include Roger Corman's The Undead, John Schlesinger's Nathanael West adaptation The Day Of The Locust, Jerry Lewis' Hardly Working and Rumplestiltskin, and Mel Brooks' Life Stinks.