He was born Willet Melbourne MacDowell in Little Washington, New Jersey (now South River, New Jersey).
MacDowell began appearing in silent films in 1917 by which time he was long a stage veteran. His co-stars were such actors as William S. Hart, Lon Chaney, Charles Ray, Enid Bennett and numerous others. Though he lived until the early 1940s, his film career ended in 1928 with the end of silent films. He returned for one sound film short in 1932, A Fool About Women with Andy Clyde and Vernon Dent.
Several films that Melbourne MacDowell appeared in survive today and can be found on DVD, particularly two of his outing with Lon Chaney, Nomads of the North and Outside the Law.