Billy Barty was born October 25, 1924, under the name William John Bertanzetti, in Millsboro, Pennsylvania. His family was of Italian descent. He was born handicapped by dwarfism. Barty became a successful film actor. He co-starred with Mickey Rooney in the Mickey McGuire silent shorts. At age nine, he played a baby escaping from a stroller. Because of his small stature, he often played children younger than himself, and also played many bit parts and gag roles. However, he played major roles in the following films: The Day of the Locust (1975), W.C. Fields and Me (1976), The Happy Hooker Goes to Washington (1977), Foul Play and The Lord of the Rings (both 1978), Under the Rainbow (1981), Night Patrol (1984), Legend (1985), Masters of the Universe (1987), Willow (1988), UHF (1989), Life Stinks and Radioland Murders (1994). 
Barty was known for his boundless energy and enthusiasm for any productions in which he appeared. He appeared in a comedy show with Spike Jones, and on a Saturday morning TV show, Dr. Shrinker. He starred in a local Southern California show, Billy Barty's Bigtop. Barty also starred as "Sigmund" in the popular children's television show Sigmund and the Sea Monsters. He did voice-overs for rides at Disney's Epcot Center.
Barty founded the Little People of America to help with his activism in obtaining rights and understanding for people who suffer from dwarfism. Barty was married to Shirley Bolingbroke of Malad City, Idaho, from 1962 until his death of heart failure, in Glendale, California, at age 76 (Dec 23, 2000). They had two children, Lori Neilson and TV/film producer and director Braden Barty. Barty and his family were members of The Church of Jesus Christ of Latter-day Saints.
A tribute book on his life was published in December 2002. Within Reach: An Inspirational Journey into the Life, Legacy and Influence of Billy Barty was produced by Barty's nephew, Michael Copeland, and Michael's wife, Debra.
Barty received a star on the Hollywood Walk of Fame in 1981.