Morris began his career as a teenager, working as a gofer and clapper boy at Wembley Studios beginning in 1932. He was later promoted to assistant cameraman, and worked on a series of "quickie" films to comply with Britain's Cinematograph Act. Following service as an RAF bomber pilot during World War II, Morris returned to film, serving as camera operator on David Lean's 1948 version of Oliver Twist. He soon rose in his profession, becoming the cinematographer for John Huston on Beat the Devil (with Humphrey Bogart and Robert Morley) and the 1956 version of Moby Dick, for which he also developed a unique color process.