During the Dust Bowl in the 1930s, William Smith's family moved to California where young Bill started his acting career at age 8 as an uncredited extra. He worked as an extra into his teen years. After graduating high school, Bill enlisted in the Air Force and served in the Korean War where he was wounded and awarded the Purple Heart. After studying at different colleges, Bill graduated cum laude from UCLA and went on to a successful career as a character actor with over 300 television and film appearances. Able to do his own stunts, he appeared in "biker" movies (most notably Run, Angel Run in 1969) and a variety of television shows which included Kolchak: The Night Stalker, Gunsmoke, The Rockford Files and Batman. In the final season of Hawaii Five-O, he played Det. James "Kimo" Carew.
A long time body builder, he had a 31-1 record as an amateur boxer and once held the Air Force Light-Heavyweight Weightlifting Championship. He had a memorable bare-knuckle fight with Clint Eastwood in the 1980 film Any Which Way You Can. In 1982, he was cast as the father of Conan the Barbarian opposite Arnold Schwarzenegger in the film of the same name.
Bill continues to act in films and television and do voice work.