David Maxwell Fyfe was born in Edinburgh, 29 May 1900, the son of William Thompson Fyfe and Isabella Fyfe (née Campbell). He was educated at George Watson's College, Edinburgh, and Balliol College, Oxford. He married Sylvia Margaret Harrison on 15 April 1925, with whom he had three daughters.

He worked for the British Commonwealth Union and acted as political secretary to Sir Patrick Hannon, 1921-2. He studied law in his spare time and was called to the Bar by Gray's Inn, 1922. He joined the chambers of George Lynskey in Liverpool, 1922. He stood as Conservative candidate for Wigan, 1924, and was adopted as Conservative candidate for Spen Valley, 1927, but was forced to withdraw when the Conservative Party reached a deal with the Liberal Party that allowed the sitting Member of Parliament, Sir John Simon, to contest the election unopposed, 1929. He was elected as Conservative Member of Parliament for Liverpool West Derby at a By-election in July 1935 and won the seat again at the General Election later that year.

He became a King's Counsel, 1934, a Bencher of Gray's Inn, 1936, and served as Recorder of Oldham, 1936-42. He joined the Army Officers' Emergency Reserve in March 1939 and was later sent to the Judge Advocate-General's Department. However, he was badly injured during an air raid in September 1940. He was Deputy Chairman, 1941-3, and Chairman, from 1943, of the Conservative Party's Central Committee on Post-War Problems. He was Solicitor-General, 1942-5, and Attorney-General, 1945. He served as British Deputy Chief Prosecutor at the Nuremberg Trials, 1945-6, where he headed the British legal team and conducted its day-to-day business in the courtroom, including a famous cross-examination of Hermann Goering. He was Shadow Minister of Labour, 1945-51; a member of the Industrial Policy Committee, from 1946; and Chairman of a Committee of Inquiry into the Conservative Party, which resulted in the Maxwell Fyfe Report, published in two parts in October 1948 and July 1949. He joined the Committee of the United European Movement, 1947, and was a member of the Assembly of the Council of Europe, where he was particularly involved in drafting the European Convention on Human Rights.

He was Home Secretary, 1951-4, and Lord Chancellor, 1954-62.

He was knighted, 1942, and made a Privy Counsellor, 1945. He was created Knight Grand Cross in the Royal Victorian Order, 1953; Viscount Kilmuir, 1954; and 1st Earl of Kilmuir and Baron Fyfe of Dornoch, 1962. He held honorary degrees from the Universities of Oxford, Manitoba, Edinburgh and Wales; was Rector of the University of St Andrews, from 1956; and Visitor of St Antony's College, Oxford, from 1953.

He died at Withyham, Sussex, 27 January 1967.

His publications include: 'Political Adventure. The Memoirs of the Earl of Kilmuir' (1964).