He made his feature film debut as an Indian in Samuel Fuller's Run of the Arrow (1957). Among his many other film credits are Run Silent, Run Deep (1958), The Slender Thread (1965), Track of Thunder (1967), The Helicopter Spies (1967), Marlowe (1969), Conquest of the Planet of the Apes (1972), The Horror at 37,000 Feet (1973), Hangar 18 (1980), Earthbound (1981), and Solar Crisis (1990). In the 1958 Walt Disney film Tonka, Wynant played Yellow Bull, a Sioux Indian, who was the cousin of White Bull, played by Sal Mineo, and is killed at the Battle of the Little Big Horn, also known as Custer's Last Stand. He also played a villain who fought Elvis Presley in It Happened at the World's Fair (1963).