Graves, born in Wimbledon (England), received his early education at Charterhouse School and won a scholarship to Oxford University (St John's College). With the outbreak of World War I he enlisted with the Royal Welch Fusiliers (RWF).
The horror of his wartime experiences had a profound effect upon him; he published his first volume of poems in 1916, but he later tried to suppress his war poetry. At the Battle of the Somme in 1916 he received such serious injuries that his family were informed of his death. However, he recovered, at the cost of permanent damage to his lungs, and spent the remainder of the war in England - despite his efforts to return to the front.
In 1917, Graves played an important part in saving his fellow poet, Siegfried Sassoon, from a court martial after the latter went absent without leave and wrote to his commanding officer denouncing the war. The two officers had become firm friends while serving with the RWF. Graves's biographies document the story well, and Pat Barker's novel, Regeneration also recounts it. Through Sassoon, Graves encountered Wilfred Owen, whose talent he recognised. Owen attended Graves's wedding to Nancy Nicholson in 1918.
In 1934 Graves published his most successful work, I, Claudius: Using classical sources he constructed a complex and compelling tale of the life of the Roman emperor Claudius, a tale extended in the sequel Claudius the God (1943). Another historical novel by Graves, Count Belisarius (1938), recounts the career of the Byzantine general Belisarius.
In 1939 Graves returned to England and began a new relationship with Beryl Hodge. In 1946 he re-established a home in Deya, Majorca, and he married Beryl in 1950. He published the controversial The White Goddess in 1948 and went on to a series of affairs and lesser amours with his 'muses'. In 1961 he became Professor of Poetry at the University of Oxford, a post he held until 1966.