At the age of 8, she played juvenile parts in
repertory theatre. She toured with
Margaret Anglin and portrayed the role of "Flora" in the original company of
The Clansman. The play continued to show for three years. During her time as a stage actress she was given the nickname "The Child Wonder." She also starred on the touring production of
Rebecca of Sunnybrook Farm and then became a screen actress. In 1908, she made her first film for the
Biograph Company. She stayed with the company until 1911. She then signed with
Independent Moving Pictures where she appeared in ingenue roles. She found success with these roles and was often cast as innocent young helpless girls which was a popular staple in films at the time. When Independent Moving Pictures and several other studios merged to form
Universal Pictures she continued working for Universal. During this time, she appeared in several short films alongside
William Garwood (who often directed the films). In 1916,
Carl Laemmle decided to open one of his eastern United States studios for Mersereau's own productions. Laemmle engaged
Oscar A. C. Lund to direct her in these features. Mersereau had always exhibited a distinct preference for working in the East, and disliked
California. Among her most successful ventures for
Blue Bird and Universal include
The Boy Girl (1917), ''Morgan's Raiders
(1918), Little Miss Nobody
(1917), Susan's Gentleman
(1917), The Honor of Mary Blake
(1916), Souls United
(1917), Autumn
(1916), and The Little Terror'' (1917). The most acclaimed project of her final period was
Nero (1922), directed by
J. Gordon Edwards, grandfather of
Blake Edwards. she continued in motion pictures into the 1920s with her final film being
The Wives of the Prophet (1926), in which she had the role of Alma. == Personal life ==