Margalo Gillmore was the daughter of Frank Gillmore, former president of Actors’ Equity, and the actress Laura MacGillivray, and the sister of actress Ruth Gillmore. Her great-aunt was the British actor-manager Sarah Thorne, and her great-uncles were the actors Thomas Thorne and George Thorne. A fourth-generation actor on her father’s side, she trained at the American Academy of Dramatic Arts. Her long stage acting career stretched from The Scrap of Paper in 1917 through to Noël Coward’s musical Sail Away on Broadway in 1961. She was first noticed by the critics in the 1919 play The Famous Mrs. Fair, which she appeared in with Henry Miller and Blanche Bates. In 1921 she played the tubercular patient Eileen Carmody in Eugene O’Neill’s The Straw. Gillmore appeared regularly with the Theatre Guild. Having appeared as an extra in a silent movie for the Vitagraph Studios in 1913 aged 16, and in a short, The Home Girl in 1928, Gillmore made her film debut in a major role in 1932 in Wayward, but didn’t appear on screen again until the 1950s, in such films as Cause for Alarm!, Perfect Strangers, High Society (1956) and Upstairs and Downstairs (1959).

During World War II. Gillmore had a role in the traveling production of The Barretts of Wimpole Street. The production starred much of the original Broadway cast, headed by leading actress Katharine Cornell, and directed by Cornell’s husband, Guthrie McClintic. The play entertained troupes in Italy, France and England and even reached within a few miles of the front in the Netherlands, and the cast made a point of visiting military hospitals every day. Television audiences may remember her as Mrs. Darling in the Broadway and televised versions of Peter Pan, which starred Mary Martin. She was a member of the famous Algonquin Round Table. Margalo Gillmore died of cancer, aged 89. Her remains were interred in Aaron Cemetery, Walker County, Alabama.