Harper was born on October 4, 1961, in Abilene, Texas. Though his own entry into the industry began in 1971, Harper is actually the son of The Wild Bunch actor Paul Harper. He made his acting debut with a bang, starting with his defining role of Jim-Bob in 1971. The Waltons began as a made-for-TV film, The Homecoming: A Christmas Story, which tells the tale of John Walton trying to return home for Christmas with his increasingly concerned family.
The cast would undergo some significant changes among the adult cast, but Harper was among the youngsters who stayed when CBS ordered a series based on the film, which in turn was inspired by the book Spencer’s Mountain by Earl Hamner Jr. It was a good thing, too, because this one-season continuation was ordered because the film was such a hit, and the show fast proved it could perpetuate that goodwill.