Donner's first role was an uncredited part in the 1959 John Wayne Western: Rio Bravo; he also appeared in the sequels (which formed a loose trilogy),: El Dorado and: Rio Lobo. He also appeared in : Chisum,: The Undefeated, and: The Man Who Shot Liberty Valance. His best-known television roles were as the ex-convict/informant T.J. on: Adam-12, Yancy Tucker on: The Waltons and as Exidor on: Mork & Mindy.