Mary O'Hara was born in Cape May Point, New Jersey. She was the third child of four born to the Reverend Dr. Reese Fell Alsop, an Episcopal clergyman, and Mary Lee Spring.
She grew up in Brooklyn Heights, New York. In 1905 she married Kent Kane Parrot and moved to California where she became a screenwriter during the silent film era. Her second marriage to Heige Sture-Vasa, in 1922, took her to Wyoming, and there she wrote the three classics about the range country: My Friend Flicka, Thunderhead and, Green Grass of Wyoming.
O'Hara was also a gifted pianist and composer. Her great love for the piano also inspired her to compose many pieces for that instrument including, "Esperan," "Green Grass of Wyoming," "May God Keep You," and "Wind Harp."
My Friend Flicka will be released in October 2006 as a feature film entitled Flicka by 21st Century Fox. It will premiere at the Hollywood Film Festival.