Famous for her roles in numerous Marx Brothers films, she is most remembered for her comedic exchanges with Groucho Marx in Duck Soup (1933) and The Big Store (1941). Also a stage actress, she appeared on Broadway in two early Marx Brothers productions: The Cocoanuts (1925) and Animal Crackers (1928).
She made her stage debut in a 1902 Chestnut Theater (Philadelphia, PA) production of Beauty and the Beast and appeared in her first silent film, A Tale of Two Cities, in 1917.
In her last film, What a Way to Go!, she played the mother of Shirley MacLaine's character.
The New York-born daughter of Harriet and William Baker, Daisy Juliette Baker (later Margaret Dumont) spent the bulk of her childhood in the southern United States, cared for by her godfather, the famous journalist and folklorist Joel Chandler Harris. Her marriage to millionaire John Moller, Jr. lasted from 1910 until Moller's death in 1918.
She appeared with Red Skelton in the 1944 movie musical Bathing Beauty.