Clarke started his career as an assistant cameraman to Allen Siegler at Universal Pictures in 1915.

He was responsible for all of the China location footage and much of the studio work for MGM's The Good Earth (1937) but was uncredited.

Whilst on the shoot for Marines, Let's Go in Japan, Clarke suffered a minor heart attack and retired from work.

However, former friend and Fox producer Kenneth Macgowan persuaded Clarke to join the Theater Arts Department at UCLA.

Clarke taught film school and wrote a book titled Professional Cinematography at the urging of his students in 1964.