Seán O’Casey, Irish playwright renowned for realistic dramas of the Dublin slums in war and revolution, in which tragedy and comedy are juxtaposed in a way new to the theatre of his time, is born at 85 Upper Dorset Street in Dublin on March 30, 1880.

Born as John Casey into a lower middle-class Irish Protestant family, his father dies when he is six, and thereafter the family becomes progressively poorer. With only three years of formal schooling, he educates himself by reading. He starts work at 14, mostly at manual labour, including several years with the Irish railways.

O’Casey becomes caught up in the cause of Irish nationalism, and he changes his name to its Irish form and learns the Irish language. His attitudes are greatly influenced by the poverty and squalor he witnesses in Dublin’s slums and by the teachings of the Irish labour leader Jim Larkin. He becomes active in the labour movement and writes for The Irish Worker. He also joins the Irish Citizen Army, a paramilitary arm of the Irish labour unions, and draws up its constitution in 1914. At this time, he becomes disillusioned with the Irish nationalist movement because its leaders put nationalist ideals before socialist ones. He does not take part in the 1916 Easter Rising against the British authorities.

Disgusted with the existing political parties, he turns his energies to drama. His tragicomedies reflect in part his mixed feelings about his fellow slum dwellers, seeing them as incapable of giving a socialist direction to the Irish cause but at the same time admirable for their unconquerable spirit.

After several of his plays have been rejected, the Abbey Theatre in Dublin produces The Shadow of a Gunman (1923), set during the guerrilla warfare between the Irish Republican Army and British forces. In 1924 the Abbey stages Juno and the Paycock, his most popular play, set during the period of civil war over the terms of Irish independence. The Plough and the Stars (1926), with the 1916 Easter Rising as its background, causes riots at the Abbey by patriots who think the play denigrates Irish heroes. When first produced in the 1920s, these plays have an explosive effect on the audiences at the Abbey and help to enlarge the theatre’s reputation.

O’Casey goes to England in 1926, meets the Irish actress Eileen Carey Reynolds, marries her, and henceforth makes England his home. His decision to live outside Ireland is motivated in part by the Abbey’s rejection of The Silver Tassie, a partly Expressionist antiwar drama produced in England in 1929. Another Expressionist play, Within the Gates (1934), follows, in which the modern world is symbolized by the happenings in a public park. The Star Turns Red (1940) is an antifascist play, and the semiautobiographical Red Roses for Me (1946) is set in Dublin at the time of the Irish railways strike of 1911.

O’Casey’s later plays, given to fantasy and ritual and directed against the life-denying puritanism he believes has beset Ireland, include Cock-a-Doodle Dandy (1949), The Bishop’s Bonfire (1955), and The Drums of Father Ned (1958). His last full-length play is a satire on Dublin intellectuals, Behind the Green Curtains, published in 1961.

O’Casey’s three indisputably great plays are The Shadow of a Gunman, Juno and the Paycock, and The Plough and the Stars. All are tragicomedies set in the slums of Dublin during times of war and revolution. Violent death and the everyday realities of tenement life throw into relief the blustering rhetoric and patriotic swagger of men caught up in the struggle for Irish independence. The resulting ironic juxtapositions of the comic and tragic reveal the waste of war and the corrosive effects of poverty. His gifts are for vivid characterization and working-class language and, though he portrays war and poverty, he writes some of the funniest scenes in modern drama. His later plays are not considered as powerful or moving as his earlier realistic plays. In his later plays he tends to abandon vigorous characterization in favour of expressionism and symbolism, and sometimes the drama is marred by didacticism.

Six volumes of O’Casey’s autobiography appeared from 1939 to 1956. They are later collected as Mirror in My House (1956) in the United States and as Autobiographies (1963) in Great Britain. O’Casey’s letters from 1910 to 1941 are edited by David Krause in two volumes (1975, 1980).

Sean O’Casey dies of a heart attack at the age of 84 on September 18, 1964, in Torquay, Devon. He is cremated at the Golders Green Crematorium.