Arthur was born Bernice Frankel to Jewish parents Philip and Rebecca Frankel in New York City on May 13, 1922. In 1933 her family moved to Cambridge, Maryland, where her parents operated a women's clothing shop. She attended Linden Hall High School, an all girls school in Lititz, Pennsylvania, before enrolling in the now-defunct Blackstone College for Girls in Blackstone, Virginia, where she was active in drama productions.

From 1947, Bea Arthur studied at the Dramatic Workshop of The New School in New York with German director Erwin Piscator. Arthur began her acting career as a member of an off Broadway theater group at the Cherry Lane Theatre in New York City in the late 1940s. On stage, her roles included Lucy Brown in the 1954 Off-Broadway premiere of Marc Blitzstein's English-language adaptation of Kurt Weill's Threepenny Opera, Yente the Matchmaker in the 1964 premiere of Fiddler on the Roof on Broadway, and a 1966 Tony Award-winning portrayal of Vera Charles to Angela Lansbury's Mame. She reprised the role in the 1974 film version opposite Lucille Ball. In 1981, she appeared in Woody Allen's The Floating Light Bulb. She made her debut at the Metropolitan Opera in 1994 portraying the Duchess of Krakenthorp, a speaking role, in Gaetano Donizetti's La fille du régiment.

In 1971, Arthur was invited by Norman Lear to guest-star on his sitcom All in the Family, as Maude Findlay, the cousin of Edith Bunker. An outspoken liberal feminist, Maude was the antithesis to the bigoted, conservative Archie Bunker, who decried her as a "New Deal fanatic". Then nearly 50, Arthur's tart turn appealed to viewers and to executives at CBS, who, she would later recall, asked "'Who is that girl? Let's give her her own series.'"

That show, previewed in her second All in the Family appearance, would be simply titled Maude. The show, debuting in 1972, would find her living in the affluent community of Tuckahoe, Westchester County, New York, with her husband Walter (Bill Macy) and divorced daughter Carol (Adrienne Barbeau). Her performance in the role garnered Arthur several Emmy and Golden Globe nominations, including her Emmy win in 1977 for Outstanding Lead Actress in a Comedy Series.

It would also earn a place for her in the history of the women's liberation movement. The groundbreaking series didn't shirk from addressing serious sociopolitical topics of the era that were fairly taboo for a sitcom, from the Vietnam War, the Nixon Administration and Maude's bid for a Congressional seat to divorce, menopause, drug use, alcoholism, nervous breakdown and spousal abuse. A prime example, "Maude's Dilemma", was a two-part episode in which Maude's character grapples with a late-life pregnancy, ultimately deciding to have an abortion. The episode aired two months before the U.S. Supreme Court legalized the procedure in the Roe v. Wade decision. Though abortion was legal in New York State, it was illegal in many regions of the country and so controversial that dozens of affiliates refused to broadcast the episode. A reported 65 million viewers watched the two episodes either in their first run that November or the following summer as a re-run. By 1978, however, Arthur decided to move on from the series.

That year, she costarred in The Star Wars Holiday Special, in which she had a song and dance routine in the Mos Eisley Cantina. She hosted The Beatrice Arthur Special on CBS on January 19, 1980, which paired the star in a musical comedy revue with Rock Hudson, Melba Moore and Wayland Flowers and Madame.

After appearing in the short-lived 1983 sitcom Amanda's (an adaptation of the British series Fawlty Towers), Arthur was cast in the sitcom The Golden Girls in 1985, in which she played Dorothy Zbornak, a divorced substitute teacher living in a Miami house owned by Blanche Devereaux (Rue McClanahan). Her other roommates included widow Rose Nylund (Betty White) and Dorothy's Sicilian mother, Sophia Petrillo (Estelle Getty). Getty was actually a year younger than Arthur in real life, and was heavily made up to look significantly older. The series became a hit, and remained a top-ten ratings fixture for six seasons. Her performance led to several Emmy nominations over the course of the series and an Emmy win in 1988. During the series run, Arthur became an LGBT icon. Arthur decided to leave the show after seven years, and in 1992 the show was moved from NBC to CBS and retooled as The Golden Palace in which the other three actresses reprised their roles. Arthur made a guest appearance in a two-part episode.

Arthur also sporadically appeared in films, reprising her stage role as Vera Charles in the 1974 film adaption of Mame, opposite Lucille Ball. Additionally, Arthur portrayed overbearing mother Bea Vecchio in Lovers and Other Strangers (1970), and had a cameo as a Roman unemployment clerk in Mel Brooks' History of the World, Part 1 (1981).

After Arthur left The Golden Girls, she made several guest appearances on television shows and organized and toured in her one-woman show, alternately titled An Evening with Bea Arthur and And Then There's Bea. She made a guest appearance on the American cartoon Futurama, in the Emmy-nominated episode "Amazon Women in the Mood", as the voice of the Femputer who ruled the giant Amazonian women. She also appeared in an episode of Malcolm in the Middle as Mrs. White, Dewey's babysitter, in a first-season episode. She was nominated for an Emmy for Outstanding Guest Actress in a Comedy Series for her performance. She also appeared as Larry David's mother on Curb Your Enthusiasm.

In 2002, she returned to Broadway starring in Bea Arthur on Broadway: Just Between Friends, a collection of stories and songs (with musician Billy Goldenberg) based on her life and career. The show was nominated for a Tony Award for Best Special Theatrical Event. The previous year had been the category's first, and there had been only one nominee. That year, Arthur was up against solo performances by soprano Barbara Cook, comedian John Leguizamo, and Arthur's fellow student in Piscator's program at The New School, actress Elaine Stritch, who won for Elaine Stritch: At Liberty.