Born Mary Jeanette Robison in Melbourne, Australia, she moved to the United States in her late teens. In 1884, she became an actress after being widowed simply to support her children. Over the next several decades, she flourished on the stage.
She starred in the 1916 silent film A Night Out, an adaptation of the play she co-wrote, The Three Lights. She made several other silent films, then successfully transitioned to talkies. She made 45 films during the 1930s. Among her starring roles was 1931's The She Wolf, in which she was cast as a miserly millionaire businesswoman, apparently a roman a clef of Hetty Green. She also starred in the final segment of the episodic classic If I Had A Million (1932) as a defeated old ladies' home resident who gets a new lease on life -- this performance received much praise. She also played the Queen of Hearts in Alice in Wonderland (1933), Countess Vronsky in Anna Karenina (1936), Aunt Elizabeth in Bringing Up Baby (1938), Aunt Polly in The Adventures of Tom Sawyer (1938), and as a sharp-tongued Granny in A Star Is Born (1937). Miss Robson was top-billed as late as 1940, starring in Granny Get Your Gun at age 82. Her last film was 1942's Joan of Paris.
In 1933, she was nominated at age 75 for the Academy Award for Best Actress for Lady for a Day, losing to Katharine Hepburn. She was the first Australian-born person to be nominated for an acting Oscar, and for many years she held the record for the oldest performer nominated for an Oscar.