Douglas McGarel Hogg was born in London, 28 February 1872, the son of Quintin Hogg and Alice Anna Graham. He was educated at Cheam School and Eton College. He married Elizabeth Marjoribanks, née Brown, in 1905 (died 1925), with whom he had two sons, and Mildred Margaret Lawrence, née Dew, in 1929 (died 1964).

He worked for eight years in the family firm of sugar merchants, Hogg, Curtis, Campbell and Co, in the West Indies and British Guiana [Guyana]. He served with the Lothian and Berwick Yeomanry in the South African War and was wounded in action. He joined Ashurst, Morris, Crisp and Co, a firm of City solicitors, and began a successful career in the law. He was called to the Bar by Lincoln's Inn, 1902; took silk as a King's Counsel, 1917; and became a bencher of Lincoln's Inn, 1920.

He also held political ambitions and was elected Conservative Member of Parliament for Marylebone, 1922-8, and appointed Attorney General, 1922-January 1924 and October 1924-8. He moved to the House of Lords when he accepted the post of Lord Chancellor, 1928-9, and the hereditary peerage that went with it. He was Secretary of State for War, 1931-5; Leader of the House of Lords, 1931-5; Lord Chancellor again, 1935-8; and Lord President of the Council, 1938.

He retired due to failing health in 1938 and spent much of his time at the family home, Carters Corner Place, near Herstmonceux, in Sussex. He died there on 16 August 1950.

He was awarded a knighthood, 1922, and created a hereditary peer as Baron Hailsham, 1928, and Viscount Hailsham, 1929.