 His credits include parts in such films as "Color Me Dead" (1969), "Ned Kelly" (1970), "The Chant of Jimmie Blacksmith" (1978), "The Survivor" (1981) and "Bush Christmas" (1983), as well as a starring role in television series "Spyforce" along with his portrayal of Bill Hayden in "The Dismissal".In an interview in 1978 for the Sir Joseph Banks High School newspaper, he revealed that he had an uncredited role off stage, controlling the Dianoga (garbage compactor monster) in "Star Wars", as well as playing the role of Lieutenant Pol Treidum in that film.Sumner played Arnie in the first series of the British science fiction drama television series "Jeopardy" in 2002, filmed in Australia.