Initially cast in minor comedic roles as the sexy, innocent young girl, she worked in numerous films for Sennett's studio.
In 1919, Sennett cast Prevost in her first lead role in Yankee Doodle in Berlin.
The film was a hit and helped to solidify Prevost's career.
She scored another success in the 1920 romantic film Love, Honor, and Behave, opposite George O'Hara, another newcomer and Sennett protégé.
By 1921, Prevost wanted to move to another studio, later stating that she left Keystone because Sennett was only interested in making money and was unconcerned with creativity.
Director King Baggot helped secure her a contract with Universal for $1,000 per week.
Prevost was released from her contract with Keystone, and she signed with Universal in 1921.

At Universal, Irving Thalberg took an interest in Prevost and became determined to make her a star.
Thalberg ensured that she received a great deal of publicity and staged numerous events which put her in the public spotlight.
After announcing that he had selected two films in which Prevost would star, The Moonlight Follies (1921) and Kissed (1922), Thalberg sent Prevost to Coney Island where she burned her bathing suit to symbolize the end of her bathing beauty days.
Initially cast in minor comedic roles as the sexy, innocent young girl, she worked in numerous films for Sennett's studio. In 1919, Sennett cast Prevost in her first lead role in Yankee Doodle in Berlin. The film was a hit and helped to solidify Prevost's career. She scored another success in the 1920 romantic film Love, Honor, and Behave, opposite George O'Hara, another newcomer and Sennett protégé. By 1921, Prevost wanted to move to another studio, later stating that she left Keystone because Sennett was only interested in making money and was unconcerned with creativity. Director King Baggot helped secure her a contract with Universal for $1,000 per week. Prevost was released from her contract with Keystone, and she signed with Universal in 1921.
At Universal, Irving Thalberg took an interest in Prevost and became determined to make her a star. Thalberg ensured that she received a great deal of publicity and staged numerous events which put her in the public spotlight. After announcing that he had selected two films in which Prevost would star, The Moonlight Follies (1921) and Kissed (1922), Thalberg sent Prevost to Coney Island where she burned her bathing suit to symbolize the end of her bathing beauty days.
Marie Prevost