As a young man he moved to Dublin, where he became associated with the Abbey Theatre; in 1915 he became its manager. Ervine served in the Royal Dublin Fusiliers during WWI, there he suffered an injury that led to the amputation of one of his legs. After the war he settled in London. Ervine's first three full-length plays, Mixed Marriage (1911), Jane Clegg (1912), and John Ferguson (1915), all tragedies, made his reputation. The First Mrs. Fraser (1928), Robert's Wife (1938), Private Enterprise (1948), and My Brother Tom (1952) are the most successful among his later plays. He also published novels; books about the theater and about politics; and biographies, including God's Soldier (1934), about William Booth, Craigavon, Ulsterman (1945), Oscar Wilde (1951), and Bernard Shaw: His Life, Work and Friends (1956). He died in London, England, on January 24, 1971. St. John Ervine was his pen name.