Born Mary Jeanette Robison. She was the youngest daughter of Henry Robison of Penrith, Cumberland, England and Julia Schelesinger of Liverpool, Lancashire, England. Her father died in 1860 and her mother remarried. In 1866/67 they were living in St Kilda, Melbourne, Victoria, Australia and moved back to London, England in 1871. She ran away from home to marry Charles Leveson Gore in 1875 and in 1877 the young couple went to Fort Worth, Texas, USA to establish a cattle ranch. They survived for two years before moving to New York where her husband died about 1881.

In 1884 she took up acting to support her three children (only her son Edward Gore survived childhood). She played both leads and supporting roles on the road and on Broadway, and over several decades she became highly respected as a character actress. She appeared in a few silent films, then returned to the screen for good in 1926 and flourished in the subsequent sound era. She was usually cast as crusty, gruff, domineering society matron or grandmother. For her portrayal of Damon Runyon's Apple Annie in Frank Capra's Lady for a Day (1933), one of her rare starring roles, she received a Best Actress Oscar nomination. Ultimately she appeared in more than 60 films, the last of which was released the year of her death.