Born the son of a graphic designer and chromolithographer, Gaunt dabbled in drawing and writing as a youth. In 1914, after winning a literary contest in the Connoisseur for an essay on Shakespeare's The Tempest, his thoughts seriously turned to becoming a critic. He served briefly in World War I, fighting in the Durham Light Infantry, 1918, until the war ended that year. The following year he attended Worcester College, Oxford, where he read modern history and participated in the Art Society. At Oxford his friends included John Rothenstein and Cyril Connolly. Graduating with honors in 1922, he studied at the Ruskin School of Drawing and wrote reviews of art exhibitions. He worked as a free-lance contributor for The Studio magazine, editing several special issues. Gaunt was fascinated by the Pre-Raphaelites, at that time undervalued as Victorian. He published in 1942 his most enduring title on that subject, The Pre-Raphaelite Tragedy. He completed an M.A. in 1926. In 1930 he published a collection of his drawings, called London Promenade. 1935 he married Mary Catherine Reilly Connolly(died, 1980). The years 1930-39 were spent writing various literary and artistic criticism, including The Pre-Raphaelite Tragedy. During the Second World-War, he took a special appointment for the war effort and researched for the book The Aesthetic Adventure. The Gaunts lived in a country cottage near the Surrey Hampshire borders.