From Wikipedia

William Fairbanks (May 24, 1894 – April 1, 1945) was an American actor. He appeared in over 65 silent era motion pictures between 1916 and 1928.

His first film role was as Capt. Pierre Thierry in the war drama Somewhere in France (1916) starring Louise Glaum and Howard C. Hickman. He was then living at 20 Horizon Avenue in Venice, California, where he registered to vote. He appeared in five movies released in 1917, including his role as Dillon in the drama The Little Brother starring Enid Bennett and William Garwood. He was then living at 115 Dudley Avenue in Venice, where he registered for the draft of World War I. He went on to serve as an ensign in the U.S. Navy.

Appearing in only one movie released in 1918, as Stuart Morley in the comedy/drama The Hired Man starring Charles Ray and Charles K. French, he was then absent from the screen for over a year due to the war. In 1920, he lived at 1309 Ocean Front in Santa Monica, and four of his movies were released that year. He was elevated to star status by independent producers Phil Goldstone and Ben F. Wilson. His screen name, taken from that of Douglas Fairbanks, whose real surname happened to be the same as his, came about with the release of his starring role in Goldstone's western Hearts of the West (1920) opposite Frances Conrad.

Although Fairbanks was a busy movie star through the greater part of the 1920s, after playing Long Collins in The Vanishing West (1928), he retired from the screen. In spite of sharing the same last name, William Fairbanks and Douglas Fairbanks Sr. were not related.