Like some young actors whose lack of experience gave them fewer opportunities on the stage, the 19-year-old Miller entered the pioneering motion picture industry and joined the Biograph Company in 1911, where he worked with D. W. Griffith.

He worked with many leading actresses of the silent screen, including Mary Pickford, Blanche Sweet, Lillian Gish, and Betty Compson.

[3] By the late 1920s he was a popular lead in serials, often opposite Allene Ray in such titles as The Way of a Man (1924), Sunken Silver (1925), Hawk of the Hills, and The Black Book (1929).

[4] The Miller-Ray partnership came to a sudden end in 1929, when the new talking-picture technology revealed that Ray's high, squeaky voice didn't fit her adventurous screen personality.

Miller kept working in features and serials until 1940, when he suffered a fatal heart attack during the filming of the Gene Autry western Gaucho Serenade.