William Boyd's filmography includes 144 credits, although he is most well-known for his portrayal of Hopalong Cassidy, the clean-cut, soft-spoken hero cowboy. Born in Oklahoma in 1895, Boyd's career began as an extra in 1918. Following a number of uncredited roles, he came to the public's notice during his star turn in Cecil B. Demille's The Road to Yesterday (1925), a role that established him as a leading man. In 1935, he won the role of Hopalong Cassidy, a character he would portray in sixty-six films and 105 radio episodes. Boyd retired to private life in 1952, living in Palm Springs, California until his death in 1972.
Source:
Guy Logsdon, “Boyd, William Lawrence,” The Encyclopedia of Oklahoma History and Culture, https://www.okhistory.org/publications/enc/entry.php?entry=BO031