Born in London, the son of a publisher, Waugh was sent to Lancing College, from which he won a scholarship to Hertford College, Oxford. On leaving university he spent three unhappy years schoolmastering, a period of failure crowned by an unconvincing attempt at suicide by drowning. A privately printed essay on the Pre-Raphaelites (1926) brought Waugh a commission for a book on Rossetti (1928), but still desperately needing money in order to marry the Hon Evelyn Gardner, he wrote Decline and Fall (1928), the first of his novels. This was an instant success, and incidentally a revenge by caricature upon the Denbighshire school in which he had taught so unsuccessfully. Waugh married in 1928 and began working on his next novel, Vile Bodies (1930). His wife was unfaithful to him and in 1930 he obtained a divorce; however, his marital position was complicated by his entry into the Roman Catholic Church in the same year. The necessary annulment was not granted until 1936; in 1937 he married again, to Laura Herbert, by whom he had six children. In the meantime he had visited Ethiopia for the coronation of Haile Selassie (1930); this journey and his subsequent travels in Africa were reported in Remote People (1931) and they also provided the background for the comic novel Black Mischief (1932). He returned to Ethiopia as a war correspondent in 1935 and 1936, visits that were the genesis of the novel Scoop (1938). In 1935 his biography of the Jesuit martyr Edmund Campion won the Hawthornden Prize.
In 1939 Waugh obtained a commission in the Royal Marines, with whom in 1941 he went to the Middle East, taking part in the battle for Crete. Put Out More Flags (1942) depicted the upper-class characters of Waugh's fictional world adapting to the rigours and opportunities of wartime. Brideshead Revisted (1945), perhaps Waugh's best-known book, centres on an aristocratic English Roman Catholic family. It was later made into an immensely successful television series.
After the war Waugh resumed his travels. The Loved One (1948) satirizes American attitudes to death and arose from a trip to California in 1947 to discuss the possibility of a film of Brideshead Revisited. Helena (1950), about the mother of Constantine the Great, was his one historical novel. He then turned to writing his war trilogy, eventually published under the title The Sword of Honour (1962), comprising Men at Arms (1952), Officers and Gentlemen (1955), and Unconditional Surrender (1961). It was hailed as one of the greatest works of fiction to emerge from World War II and was also made into a TV series. The Ordeal of Gilbert Pinfold (1957) is a thinly fictionalized account of the hallucinations Waugh himself suffered after taking excessive doses of sleeping tablets. In 1959 Waugh's biography of his friend Monsignor Ronald Knox appeared. His last travel book was A Tourist in Africa (1960). He then turned to writing his autobiography but completed only the first volume, A Little Learning (1964), before his death.