MacPherson made her film debut in the 1908 film
The Fatal Hour, directed by
D. W. Griffith. She acted in many controversial roles in which she portrayed characters of ethnicities other than her own; due to her dark hair, she was often cast in
Gypsy or Spanish roles. From 1908 to 1917, she amassed 146 acting credits. She saw her time with Griffith as her "first glimmer of the possibilities in the new industry [and] from those days on [she had] seen a variety of attitudes toward the scriptwriters." After working with Griffith, MacPherson began working with the
Universal Company, where she starred in more prominent roles. In 1913, she wrote, directed and starred in
The Tarantula, about a Spanish-Mexican girl, known as the Tarantula, who seduced men before killing them. With this film, she became the youngest director in motion picture history.
The Tarantula is the only film she directed. MacPherson continued working for the Universal Company for two years, until her failing health caused her to leave. Upon her recovery, MacPherson began working for
Lasky Studios; however, she quickly sought out
Cecil B. DeMille to see if she could act in his films. He told her, "I am not interested in star MacPherson, but I am in writer MacPherson"; and from that point on, she focused on writing. DeMille and MacPherson formed a partnership that some scholars consider to be one of the industry's most influential and long-lasting. MacPherson wrote the scripts for 30 of DeMille's next 34 films. Some of their most notable collaborations are
Rose of the Rancho (1914) starring
Bessie Barriscale,
The Girl of the Golden West starring
Mabel Van Buren,
The Cheat (1915) starring
Sessue Hayakawa,
The Golden Chance (1915) starring
Wallace Reid,
Joan the Woman (1916) starring
Geraldine Farrar,
A Romance of the Redwoods (1917) with
Mary Pickford,
The Little American again starring Pickford, and
The Woman God Forgot (1917) again starring Farrar. ,
John Cumpson and Tony O'Sullivan in
Mrs. Jones Entertains (1909) In 1921, MacPherson told a reporter, "I shall always be grateful for Mr. DeMille's assistance. He is a hard taskmaster, and he demands that a thing shall be perfect... It was hard, but it taught me that anything worth doing at all was worth doing perfectly." MacPherson believed that motion picture owed its psychology to D. W. Griffith and its dramatic picture scenario construction to DeMille. In 1927, she became a founding member of the Academy of Motion Picture Arts and Sciences. ==Personal life==