Born Marie Anne Boland in Girardville, Mary Boland was the daughter of repertory actor William Boland, and his wife Mary Cecilia Hatton. She had an older sister named Sara. The family later moved to Detroit. Mary Boland went to school in the classy Convent of the Sacred Heart in Detroit. By the age of fifteen she had left school and was performing on stage. She debuted on Broadway in 1907 in the play The Ranger with Dustin Farnum and had appeared in eleven Broadway productions, notably with John Drew, before making her silent film debut for Triangle Studios in 1915. She entertained soldiers in France during World War I then returned to America. After appearing in nine movies, she left filmmaking in 1920, returning to the stage and appearing in a number of Broadway productions. She became famous as a comedian. Boland’s greatest success on the stage in the 1920s was the comedy The Cradle Snatchers (1925–26), in which she, Edna May Oliver, and Margaret Dale, having been abandoned by their husbands, take on young lovers. Boland’s paramour was Humphrey Bogart in one of his first roles. She had previously performed with Bogart in the 1923 comedy Meet the Wife at the Klaw Theatre as Gertrude Lennox. After an eleven-year absence, in 1931 she returned to Hollywood under contract to Paramount Pictures. She achieved far greater film success with her second try, becoming one of the 1930s most popular character actresses, always playing major roles in her films and often starring, notably in a series of comedies opposite Charles Ruggles.

Mary Boland appeared in numerous films, including Ruggles of Red Gap, The Big Broadcast of 1936, Danger – Love at Work, Nothing but Trouble, and Julia Misbehaves. She is likely best remembered for her portrayals of Countess DeLave in The Women (1939) and Mrs. Bennet in Pride and Prejudice (1940). For the remainder of her career, Boland combined films and, later television productions, with appearances onstage (including starring in the 1935 Cole Porter musical Jubilee), making her last Broadway appearance in 1954 at the age of seventy-two. That play, Lullaby, was not a success. Her last acting was done in the 1955 television adaptation of The Women recreating her film role. Mary Boland never married or had children. She died of a heart attack and was interred in the Great Mausoleum, Sanctuary of Vespers in Forest Lawn Memorial Park Cemetery in Glendale, California. For her contribution to the motion picture industry, she has a star on the Hollywood Walk of Fame at 6150 Hollywood Boulevard.