Eugene O'Neill (1888–1953) was the son of an actor whose work meant that the family led a difficult life on the road. O'Neill would later deeply resent his insecure childhood, pinning the family's many problems, including his mother's drug addiction, on his father. Educated at boarding schools, O'Neill gained admission to Princeton University but left after only one year to go to sea. He spent his early twenties living on the docks of Buenos Aires, Liverpool, and New York, sinking into an alcoholism that brought him to the point of suicide. Slowly O'Neill recovered from his addiction and took a job writing for a newspaper. A bout of tuberculosis left him incapacitated and he was consigned to a sanitarium for six months. While in recovery, O'Neill decided to become a playwright.

O'Neill wrote his first play, Bound East for Cardiff, in 1916, premiering it with a company in Provincetown, MA that took it to New York that same year. In 1920, O'Neill's breakthrough came with his play Beyond the Horizon. Historians of drama identify its premiere as a pivotal event on the Broadway stage, one that brought a new form of tragic realism to an industry almost entirely overrun with stock melodramas and shallow farces. O'Neill went on to write over twenty innovative plays in the next twenty years, to steadily growing acclaim. The more famous works from his early period include The Great God Brown (1926), a study in the conflicts between idealism and materialism, and Strange Interlude (1928), an ambitious 36-hour saga on the plight of the Everywoman. His late career brought such works as his masterpiece, The Iceman Cometh (1946), an Ibsenian portrait of man's hold on his pipe dreams, and A Long Day's Journey into Night (1956), the posthumously published and painfully autobiographical tragedy of a family haunted by a mother's drug addiction.

O'Neill wrote morality plays and experimented with the tragic form. O'Neill's interest in tragedy began as early as 1924 with his Desire Under the Elms, a tale of incest, infanticide, and fateful retribution, but would come to maturity with his monumental revision of Aeschylus's Oresteia,Mourning Becomes Electra (1931). O'Neill chose Electra because he felt that her tale had been left incomplete. More generally, as his diary notes indicate, O'Neill understood his exercises in tragedy as an attempt to find a modern analogue to an ancient mode of experience. Thus Mourning aims to provide a "modern psychological approximation of the Greek sense of fate" in a time in which the notion of an inescapable and fundamentally non-redemptive determinism is incomprehensible. Accordingly, the setting of the trilogy, the American Civil War, springs from O'Neill's attempt to negotiate the chasm between ancient and modern. For O'Neill, the Civil War provided a setting that would allow audiences to locate the tragic in their national history and mythology while retaining enough distance in time to lend the tale its required epic proportions. Mourning also provided O'Neill with an occasion to abandon the complex set design of the Art Theater, which he had long bemoaned as a constraint on the playwright's creative freedom.