 He served as a soldier during World War II.After that, he resumed work in 1955, and began a long, fruitful collaboration with producer-director Roger Corman, which led to a busy career in low-budget independent filmmaking.Sinclair edited Corman's directorial debut, "Swamp Women", and went on to work on at least a dozen of Corman's other films including "Day the World Ended", "The Intruder", "Thunder Alley", "The Raven" and "The Trip".