Redgrave was born in Marylebone, London, to actors Sir Michael Redgrave and Rachel Kempson. Her sister is actress Vanessa Redgrave; her brother was actor and political activist Corin Redgrave. She was the aunt of writer/director Carlo Gabriel Nero and actresses Joely Richardson, Jemma Redgrave and Natasha Richardson and the sister in law of the director Tony Richardson, the Italian actor Franco Nero and the actress Kika Markham. Her grandfather was silent screen leading man Roy Redgrave.

After training in London’s Central School of Speech and Drama, Redgrave made her professional debut in a 1962 production of A Midsummer Night’s Dream at the Royal Court Theatre. Following a tour of Billy Liar and repertory work in Dundee, she made her West End debut at the Haymarket, in N. C. Hunter’s The Tulip Tree with Celia Johnson and John Clements.  She was invited to join The National Theatre for its inaugural season at the Old Vic, working with such directors as Laurence Olivier, Franco Zeffirelli, and Noël Coward in roles such as Rose in The Recruiting Officer, Barblin in Andorra, Jackie in Hay Fever, Kattrin in Mother Courage, Miss Prue in Love for Love, and Margaret in Much Ado About Nothing which kept her busy for the next three years.  During that time she appeared in films such as Tom Jones (1963), Girl with Green Eyes (1964), The Deadly Affair (1966) and the title role in Georgy Girl (also 1966, and which featured her mother, Rachel Kempson). For the last of these roles she gained the New York Film Critics Award, the Golden Globe and an Oscar nomination.

In 1967 she made her Broadway debut in Black Comedy with Michael Crawford and Geraldine Page. London appearances included Michael Frayn’s The Two of Us with Richard Briers at the Garrick, David Hare’s Slag at the Royal Court, and Born Yesterday, directed by Tom Stoppard at Greenwich in 1973.  In 1974, she returned to Broadway in My Fat Friend. There soon followed Knock Knock with Charles Durning, Mrs Warren’s Profession (for a Tony nomination) with Ruth Gordon, and Saint Joan. In the 1985-86 season she appeared with Rex Harrison, Claudette Colbert and Jeremy Brett in Aren’t We All? and with Mary Tyler Moore in A. R. Gurney’s Sweet Sue.  In 1983, she played Cleopatra in an American television version of Antony and Cleopatra opposite Timothy Dalton. She was in Misalliance in Chicago with Irene Worth, (earning the Sarah Siddons and Joseph Jefferson awards), Twelfth Night at the American Shakespeare Festival, California Suite, The King and I, Hellzapoppin’, Les Dames du Jeudi, Les Liaisons Dangereuses and The Cherry Orchard. In 1988 she narrated a dramatised television documentary, Silent Mouse, which told the story of the creation of the Christmas carol Silent Night. In the early winter of 1991 she starred with Stewart Granger and Ricardo Montalban in a Hollywood production of Don Juan in Hell.

With her sister Vanessa as Olga, she returned to the London stage playing Masha in Three Sisters in 1991 at the Queen’s Theatre, London, and later played the title role in a television production of Whatever Happened to Baby Jane?, again with her sister. Highlights of her early film career also include The National Health, Everything You Always Wanted to Know About Sex* (*But Were Afraid to Ask), The Happy Hooker and Getting It Right. In the United States she was seen on such television series as Teachers Only, House Calls, Centennial and Chicken Soup.  She also starred in BBC productions such as The Faint-Hearted Feminist, A Woman Alone, Death of a Son, Calling the Shots and Fighting Back. She played Broadway again in Moon Over Buffalo (1996) with co-star Robert Goulet, and starred in the world premier of Tennessee Williams’ The Notebook of Trigorin, based on Anton Chekhov’s The Seagull. She won the Drama Desk Award for Outstanding Featured Actress in a Play for her performance in Talking Heads.

Redgrave became well known in the United States after appearing in the television series House Calls, for which she received an Emmy nomination. She was sacked from the show after she insisted on bringing her child to rehearsals so as to continue a breast-feeding schedule. A lawsuit ensued but was dismissed a few years after. Following that, she appeared in a long-running series of television commercials for H. J. Heinz Company, then the manufacturer of the weight loss foods for Weight Watchers, a Heinz subsidiary. Her signature line for the ads was “This Is Living”. She wrote a book of her life experiences with the same title, which included a selection of Weight Watcher recipes. The autobiographical section later became the basis of her one-woman play Shakespeare for My Father.  In 1993 she was elected President of the Players’ Club. In 1989 she appeared on Broadway in Love Letters with her husband John Clark, and thereafter they performed the play around the country, and on one occasion for the jury in the O. J. Simpson case. In 1993 she appeared on Broadway in the one-woman play Shakespeare for My Father, which Clark produced and directed. She was nominated for the Tony Award for Best Actress in a Play. In 1993, she voiced The Narrator and one of the characters on the cartoon christmas movie Precious Moments Timmy’s Special Delivery.

In 2005, Redgrave appeared at Quinnipiac University and Connecticut College in the play Sisters of the Garden, about the sisters Fanny and Rebekka Mendelssohn and Nadia and Lili Boulanger. She was also reported to be writing a one-woman play about her battle with breast cancer and her 2003 mastectomy, based on her book Journal: A Mother and Daughter’s Recovery from Breast Cancer with photos by her daughter Annabel and text by Redgrave herself.  In September 2006, she appeared in Nightingale, the U.S. premiere of her new one-woman play based upon her maternal grandmother Beatrice, at Los Angeles’ Mark Taper Forum. She also performed the play in May 2007 at Hartford Stage in Hartford, Connecticut. In 2007, she appeared in an episode of Desperate Housewives as Dahlia Hainsworth.  She also appeared on an episode of ABC’s TV series Ugly Betty and Desperate Housewives as Dahlia, the mother of Susan Delfino’s boyfriend Ian Hainsworth, and an episode of Law & Order: Criminal Intent.

She discussed her health problems associated with bulimia and breast cancer. She was diagnosed with the latter in December 2002, had a mastectomy in January 2003, and chemotherapy. She died from breast cancer in her Kent, Connecticut, home on 2 May 2010, aged 67. Her brother, actor Corin Redgrave, who had also been a cancer patient in his last years, had died less than one month previously, on 6 April, aged 70. She was survived by her three children, her six grandchildren and her elder sister Vanessa.  Redgrave’s funeral was held on 8 May at the First Congregational Church in Kent, Connecticut. She was interred in St. Peter’s Episcopal Cemetery in the hamlet of Lithgow, New York, where her mother, Rachel Kempson, and niece, Natasha Richardson, are also interred.