Born Sarah Blanche Sweet in Chicago, Illinois into a family of stock theater and vaudeville performers, Blanche Sweet entered the entertainment industry at an early age and first appeared on the stage when she was 18 months old. In 1909, she started work at Biograph Studios under contract to director D. W. Griffith. By 1910 she had become a rival to Mary Pickford and starred in such films as The Lonedale Operator (1911) and Judith of Bethulia (1914).
Sweet is renowned for her energetic, independent roles, at variance with the 'ideal' Griffith type of vulnerable, often fragile, femininity. In 1913 she starred in Griffith's first feature-
During the early 1920s Sweet's career continued to prosper, and she starred in the first film version of Anna Christie in 1923 directed by John Griffith Wray. The film is also notable as being the first Eugene O'Neill play to be made into a motion picture. In successive years, she starred in Tess of the D'Urbervilles and The Sporting Venus, both directed by Neilan. Sweet soon began a new career phase as one of the newly formed MGM studio's biggest stars.
As the "Roaring Twenties" wound down, Sweet's career faltered with the advent of talkies. Sweet made just three talking pictures, including her critically lauded performance in 1930's Show Girl in Hollywood, before retiring from the screen that same year.