Ellen Stewart was either born in Chicago, Illinois or possibly Alexandria, Louisiana. This inexactitude stems from Stewart’s reticence about revealing details of her early life. As an observer wrote, “Her history is somewhat difficult to sort out—indeed it takes on a legendary quality—since on different occasions she gives different versions of the same stories.”  Of her parents, Stewart stated that her father was a tailor from Louisiana and her mother was a teacher and that they divorced during her youth.  Around 1939 Stewart may have become the second wife of Larry Lebanus Hovell (born August 10, 1910 — died October 1963, a Chicago waiter who was a native of Alexandria, Louisiana, although it is possible they never legally wed. They had one child, a son, Larry Lebanus Hovell, II (1940—1998).

In 1950 Stewart moved to New York City, where she worked as a trimmer in the brassiere-and-corset department at Saks Fifth Avenue and, later as a dress designer, under the direction of Edith Lances, head of the department store’s custom-corset department. Stewart continued to work as a fashion designer throughout the 1960s and 1970s, notably for a manufacturer called Victor Bijou, where she designed “sport dresses and beach wraps”.  In 1961 Stewart together with Paul Foster and others founded Café La MaMa, which became one of the most successful Off-Off-Broadway theatrical companies – La MaMa Experimental Theatre Club. In the next decades she became famous around the world, writing and directing an enormous body of pieces, exclusively based on music and dance, with international artists.  In 1992, Stewart was inducted into the American Theater Hall of Fame.

In 2007 Stewart was awarded the Praemium Imperiale in the field of Film and Theater and the Stanislaw Ignacy Witkiewicz Award granted annually by the Polish Centre of the International Theatre Institute for “outstanding achievements in the promotion of Polish theatre throughout the world”.  In 2005 Tom O’Horgan presented Stewart with the Stewardship Award from the New York Innovative Theatre Awards. This honor was bestowed to Stewart on behalf of her peers and fellow artists of the Off-Off-Broadway community “in recognition of her significant contributions to the Off-Off-Broadway community through service, support and leadership”.

Ellen Stewart died on January 13, 2011, aged 91. Stewart had a history of heart trouble and died at Beth Israel Hospital, New York City, after a long illness. Her memorial service was held at the St. Patrick’s Cathedral in New York City on Monday, January 17, 2011.