Contrary to popular belief, she was not related to "All in the Family" (1968) star Jean Stapleton.
Following her second divorce, she had a long affair with legendary Broadway fixture George Abbott that began when she was 43 and he was 81. It ended 10 years later when the director cheated on her with a younger woman.
Had a self-admitted drinking problem (her Irish-born father was a heavy drinker) and confessed that she would head for the vodka right after the curtain went down. Liquor was a fixture in her dressing room but claims she never appeared on stage drunk.
Has won two Tony Awards: in 1951, as Best Supporting or Featured Actress (Dramatic) for "The Rose Tattoo," and in 1971, as Best Actress (Dramatic) for "The Gingerbread Lady." She has also been nominated four other times: as Best Actress (Dramatic), in 1959 for "The Cold Wind and the Warm," in 1960 for "Toys in the Attic," and in 1968 for "Plaza Suite;" and in 1981, as Best Actress (Featured Role - Play) for "The Little Foxes."
In 1959 she became the first actor to receive an Oscar, Emmy and Tony nomination in the same year (for Lonelyhearts (1958), All the King's Men (1958) (TV) and "The Cold Wind and the Warm", respectively).
In 1963 she appeared in "Bye Bye Birdie" as Dick Van Dyke's mother. In fact, she was born the same year as Van Dyke.
In 1981, Hudson Valley Community College in her hometown of Troy, New York, named their theatre after her.
In 1981, she became the tenth performer to win the Triple Crown of acting. Oscar: Best Supporting Actress, Reds (1981), Tony: Best Supporting Actress-Play, 'The Rose Tattoo' (1951), and Emmy: Best Actress-Drama, Among the Paths to Eden (1967) (TV).
Inducted into the Theatre Hall of Fame on April 5, 1981.
Is one of twelve actresses to have won the Triple Crown of Acting (an Oscar, Emmy and Tony); the others in chronological order are Helen Hayes, Ingrid Bergman, Shirley Booth, Liza Minnelli, Rita Moreno, Jessica Tandy, Audrey Hepburn, Anne Bancroft, Vanessa Redgrave, Maggie Smith and Ellen Burstyn.
Is the fourth of four consecutive winners of the Best Supporting Actress Oscar to have the initials "M.S.". The others are: Maggie Smith (California Suite (1978)), Meryl Streep (Kramer vs. Kramer (1979)) and Mary Steenburgen (Melvin and Howard (1980)).
Member of the Academy of Motion Picture Arts and Sciences (Actors Branch)
Mother of two children by her first husband, Max Allentuck: Daniel V. Allentuck and Katherine Allentuck (Bambery).
Once joined the Actors Studio, whose members included Marlon Brando who sometimes crashed in her one-room NY apartment.
Received a 1975 Grammy Award nomination in the Best Spoken Word category for her recording of "To Kill a Mockingbird".
Received a special tribute as part of the Annual Memorial tribute at The 79th Annual Academy Awards (2007) (TV).
Received the Actors Studio Award in 1980 for her contributions to the theatre.
She did not travel by air or elevator. She traveled by rail across the country, and traveled by ship across the ocean, instead of by plane.
She originated the role of Serafina in Tennessee Williams' "The Rose Tattoo" on Broadway in 1951 and Lady Torrance in Williams' "Orpheus Descending" in 1957. Both roles were played by Anna Magnani in the movie versions. Stapleton appeared in the film version of "Orpheus Descending", retitled The Fugitive Kind (1959), but in a supporting role.
She studied drama at HB Studio in Greenwich Village in New York City.