[2] Mary and her younger sister, author/actress Florence, were born to James H. Ryan, a lawyer, and his wife, Ellen Frances (née McNamara).

[3] The sisters adopted the surname of their stepfather, Philip F. Nash, a vaudeville booking executive, who married their mother after the death of their father.

After brief appearances as a dancer at the Herald Square Theatre in 1904, she made her off-Broadway debut on Christmas Day 1905 as Leonora Dunbar in James M. Barrie's Alice-Sit-by-the-Fire, which starred Ethel Barrymore.

Her last Broadway appearance was a production of Uncle Tom's Cabin in 1933 as Cassie, which starred Otis Skinner and Fay Bainter.

"[5] In the 1940 film Gold Rush Maisie, she played the patient, forbearing wife and mother of a family, forced by the Dust Bowl and Depression to abandon their farm in Arkansas, that has spent five years traveling through the country in search of seasonal work.