In 1912-13, while a tuberculosis patient in the Gaylord Sanitarium, Eugene O'Neill decided to become a dramatist. As a result American drama during the first half of the twentieth century was totally changed, and a new high seriousness came into the theatrical market place. Dissatisfied with the old histrionic romantic theatre of his father (James O'Neill, the perennial Count of Monte Cristo), Eugene O'Neill made profitable use of his three-month hospital stay by reading philosophy, drama, and absorbing the influence of new theatrical movements in Ireland, France, Sweden, and Germany, led by J. M. Synge, Eugene Brieux, August Strindberg and Gerhart Hauptmann.

On his release from Gaylord he started to write, using his own life experiences as creative matrix. Thus he set the autobiographical pattern that was to culminate in the great family plays of his last years: Long Day's Journey Into Night and A Moon for the Misbegotten, with a return to the dissipation of his youth in The Iceman Cometh.