English drama critic for the London Sunday Times (1923–47), book reviewer for the Daily Express, novelist, essayist, diarist, and raconteur. He is remembered for his wit and perverse yet lovable personality, the sparkle and fundamental seriousness of his dramatic criticism, and his racy, entertaining diary, called, characteristically, Ego, 9 vol. (1932–47).

Educated at the Giggleswick and Manchester grammar schools, Agate went to London to become a journalist, working as drama critic for several papers. During World War I he served as an army officer. Between 1917, when, as he said, he “stormed London” with a lively account of an uneventful war, and 1949, 44 volumes of his drama, book, and film reviews, essays, novels, and surveys of the contemporary theatre for 1923–26 and 1944–45 had been published, not counting the nine volumes of Ego. He was perhaps one of the last of a long line of English dramatic critics to take for granted his position as arbiter of taste and was also one of the last outstanding journalists of a great age of English journalism.