Born into a large, eccentric Brooklyn family, Davies and most of her sisters took to the stage by their early teens. With her China-doll blonde beauty and high spirits, she made a hit in such shows as "The Blue Bird" (her debut, 1910), "Chu Chin Chow" (1913), "Oh, Boy!" and "The Ziegfeld Follies" (both 1917). She had also made her first film, "Runaway Romany" (1917), when she met Hearst. Her subsequent career became a rollercoaster ride (on which Davies was often an unwilling passenger).
Hearst formed Cosmopolitan, a production company distributing films first through Paramount (1919-23), then Goldwyn (1924-25), then MGM (1925-34) and finally Warner Brothers (1935-37). In the late 1910s and early 20s, Davies was showcased in huge, romantic and mostly historical epics such as "The Belle of New York" (1919), "When Knighthood Was in Flower" (1922), "Lights of Old Broadway" (1925) and "Beverly of Graustark" (1926). These films were not by any means as bad or unsuccessful as posterity would have it, but Davies was uncomfortable in drama, and Hearst's high-pressure public relations campaigns alienated the press and public alike. Happily, Davies was given more comedy towards the end of the silent era.
She was seen at her peak in such hilarious late silent comedies as "The Patsy" and "Show People" (1928), in which her playful, self-mocking vivacity and flair for mimicry were shown to excellent advantage. Several of her sound films were quite enjoyable, including "Blondie of the Follies" (1932) and "Going Hollywood" (1933, co-starring rising young crooner Bing Crosby), but Davies also had the ill fortune to appear in such lame farces as "Ever Since Eve" (1937) and the ill-conceived period romance "Operator 13" (1934).
A famous and well-liked party giver who never took her stardom very seriously, Davies remained active in Hollywood's social scene after she made her last film in 1937. She was also a clever businesswoman, investing in real estate and contributing to many charities, as well as working for John F. Kennedy's presidential bid in 1960. Disowned by the Hearst family after his death, Davies married an old friend and died in 1961. On the 1993 death of her "niece" Patricia van Cleve, it was announced by the family that van Cleve was indeed Davies' and Hearst's daughter, born in the mid-1920s.