From the 1930's to the 1950's, he was regarded as the doyen of British film editors. Harris began his career in 1921 at the original Shepherd's Bush Gaumont Studios. After the advent of sound, he worked at Twickenham, often on quota quickies. He was associated with David Lean's films in the 1940's and was briefly supervising editor at Pinewood at the end of the decade. During the 1950's, he worked on several classic films at Ealing.