 At the age of four, Provost was cast in the film "The Country Girl" (1954), starring Bing Crosby and Grace Kelly.He then appeared in "Back from Eternity" (1956) with Anita Ekberg and "Escapade in Japan" (1957), with Teresa Wright, Cameron Mitchell, and an unknown and uncredited Clint Eastwood.In 1957, Provost won the role of Timmy Martin in the CBS television series "Lassie".