Peter Ostrum was born in Dallas, Texas in 1957, but spent a substantial portion of his childhood in Cleveland, Ohio. It was in Cleveland that he began acting professionally, appearing in children's theater productions at the Cleveland Play House. The story goes that talent scouts from Paramount, sometime in 1970, were scouring children's theaters looking for potential actors to play the five central children in a film adaptation of Roald Dahl's confection-based 1964 novel "Charlie and the Chocolate Factory."

The 12-year-old Ostrum was asked to pose for a few Polaroids and was recorded reading passages from Dahl's book into a tape recorder. He also sang "My Country 'Tis of Thee" as proof of his singing abilities. The pictures and recordings were then flown to New York and shown to the film's producers. Ostrum was perfect and beat out many, many other children for the role of Charlie Bucket. His experience on stage gave him an edge.