Corin Redgrave was part of the third generation of a theatrical dynasty spanning four generations. His parents were Sir Michael Redgrave and Rachel Kempson; Vanessa and Lynn Redgrave were his sisters. His first marriage was to Deirdre Deline Hamilton-Hill (1939–1981). They had a daughter, Actress Jemma Redgrave, and a son, Luke, a camera operator and production assistant. Redgrave and Hamilton-Hill divorced in 1975. Redgrave and Kika Markham married in 1985 in Wandsworth, London, and remained together until Redgrave's death. The couple had two sons, Harvey (born 1979) and Arden (born 1983).

On screen he is best known for his roles in such acclaimed and diverse films as A Man for All Seasons (1966) as Thomas More's son-in-law; william Roper, Excalibur (1981) as the doomed Cornwall, In the Name of the Father (1993) as the corrupt lead police investigator, Persuasion and Four Weddings and a Funeral (1994) as Hamish, the fiancée of Andie MacDowell's character.

Redgrave appeared in British television programmes such as Ultraviolet, The Vice, Trial & Retribution, Shameless, Foyle's War, The Relief of Belsen, The Ice House and the Emmy Award-winning telefilm The Girl in the Cafe, in which he played the prime minister. He took the lead part of Sir George Grey in the New Zealand TV miniseries The Governor (1977).

For his role as the prison warden Boss Whalen in the Royal National Theatre production of Tennessee Williams's Not About Nightingales, Redgrave was nominated for an Evening Standard Award, and after a successful transfer of the production to New York, he received a Tony Award nomination for Best Actor in a Play, in 1999. Two years later he starred in the original London production of The General from America as Benedict Arnold. When the play transferred to Broadway the following season Redgrave switched roles and portrayed George Washington .

Redgrave was diagnosed with prostate cancer in 2000, which continued to affect him until he died in 2010. In June 2005, he was described by his family as being in a critical but stable condition in hospital following a severe heart attack at a public meeting in Basildon, Essex. In March 2009, Redgrave returned to the London stage playing the title role in Trumbo, based on the life of the blacklisted Hollywood Screenwriter Dalton Trumbo. On the opening night, Redgrave dedicated his performance to the memory of his niece Natasha Richardson who had died earlier that week in a skiing accident.

He wrote a play called Blunt Speaking, in which he performed at the Minerva Theatre (a second stage of the Chichester Festival Theatre) between 23 July - 10 August 2002. (review The Mail on Sunday, 28 July 2002)

In 2005, Redgrave had just finished an engagement playing the lead in King Lear with the Royal Shakespeare Company in London when he suffered a severe heart attack. In 2008, he returned to the stage in a highly praised portrayal of Oscar Wilde in the one-man-play De Profundis. In 2009, he starred in Trumbo, which opened only hours after the death of his niece, Natasha Richardson.

His ex-wife Deirdre died of cancer in 1997. His sister Lynn Redgrave died of breast cancer on 2 May 2010, less than a month after her brother. Kika Markham's memoir of her husband, Our Time of Day: My Life with Corin Redgrave, was published in 2014.