Mini Biography from IMDB.com

Forever associated with a heroic TV collie whom he frequently had his arms lovingly wrapped around, blond tyke Jon Provost actually was a veteran performer by the time he won the role of "Timmy Martin" at age seven in the series "Lassie" (1954). L.A. born and bred, Jon was just three years old when he was cast as Jane Wyman and Sterling Hayden's son in the film So Big (1953). He proceeded with The Country Girl (1954) as Bing Crosby and Grace Kelly's son, Back from Eternity (1956) starring Anita Ekberg, and co-starred in Escapade in Japan (1957), which featured an unknown (and unbilled) Clint Eastwood. And then came "Lassie" (1954)... Actor Tommy Rettig, as Lassie's original young master "Jeff Miller", had become too old to be romping around with his dog, so in 1957, he moved away to college and his entire family sold the farm to a brand new clan -- The Martins. Jon's parents were played by rangy Hugh Reilly and the ever-wholesome June Lockhart. For seven seasons, audiences grew to love Timmy and his perilous adventures with the invincible canine. By 1964, however, the Martin family decided to move to Australia and Jon's reign was over as a child star. His post-Lassie years were difficult, however, and by the time he was eighteen, decided to quit and go to college. He graduated with a psychology degree and worked for a time in the field of special education. Later, he sold real estate in Sonoma Country (California) while donating his time (and celebrity) to highly worthy causes. In 1991, out of nowhere, Jon returned to TV with a recurring role in "The New Lassie" (1989) series--as a real estate agent. In one nostalgic episode, he appeared together with Lassie's original master, Tommy Rettig, who was making a guest appearance. At age 50+, Jon continues to show up at celebrity conventions.