Lynn Redgrave's first film role was in a small part in Tom Jones in 1963. In 1966 she was nominated for the Academy Award for Best Actress for Georgy Girl. She has worked on television, the London stage, and Broadway. She has twice been nominated for Tony Awards and is the 1977 and 1995 winner of the Sarah Siddons Award for her work in Chicago theatre.

Other films include The Happy Hooker, Every Little Crook and Nanny, Everything You Always Wanted to Know About Sex (But Were Afraid to Ask), The Big Bus, Sunday Lovers and Morgan Stewart's Coming Home. From 1979 to 1981, she starred in the American television series House Calls. In 1998 she appeared in Strike! and was nominated for the Academy Award for Best Supporting Actress for Gods and Monsters. In her latest film, Kinsey, which starred her nephew-in-law, Liam Neeson, she has a brief but poignant and widely praised role.

In 2000, Redgrave divorced her husband of 33 years, producer John Clark, when it was revealed that he had fathered a child with his assistant. The assistant eventually married, then divorced, Redgrave and Clark's son Benjamin. Several years ago, Redgrave announced that she has breast cancer. She has written a play, The Mandrake Root, in which she will star. As of March 23, 2005, the website of Quinnipiac University in Hamden, Connecticut states that she will be appearing live on stage in the play Sisters of the Garden, about the Mendelssohn and Boulanger sisters, on March 30, 2005. As of early 2005, she is reported to be writing a one-woman play about her battle against cancer, from which she is evidently in remission, and her 2002 mastectomy, based on her book Journal: A Mother and Daughter's Recovery from Breast Cancer with photos by Annabel Clark (Redgrave's youngest daughter) and text by Redgrave herself.

Redgrave was appointed an Officer of the Order of the British Empire, although she later became a naturalized citizen of the U.S.. She narrated Prince Caspian by C.S. Lewis for Harper Audio.