Ostrum was 12 years old when selected by talent agents for Willy Wonka. Though he enjoyed the experience of shooting the film, he opted not to sign a three-film contract when it was over. After eschewing a career in film and theatre, Ostrum became reluctant to speak about his one starring role. In 1990, he began an annual tradition of speaking to schoolchildren about the film, and he became a subject of interest again when the 2005 film Charlie and the Chocolate Factory was released to theaters.

Ostrum became interested in his family's horses when he returned from shooting Willy Wonka, and was particularly influenced by the veterinarian that tended to them. He received a Doctorate of Veterinary Medicine from Cornell University College of Veterinary Medicine in 1984. As of 2021, Ostrum practiced and lived in Glenfield, New York with his wife Loretta (née Lepkowski), having raised two children.

Description above from the Wikipedia article Peter Ostrum, licensed under CC-BY-SA, full list of contributors on Wikipedia.