In key aspects, the play closely parallels Eugene O'Neill's own life. The location, a summer home in Connecticut, corresponds to the family home, Monte Cristo Cottage, in New London, Connecticut (the small town of the play), and in real life the cottage is today made up as it may have appeared in the play. The family corresponds to the O'Neill family, which was Irish-American, with three name changes: the family name "O'Neill" is changed to "Tyrone," the name of the earldom granted to Conn O'Neill by Henry VIII; the names of the second and third sons are reversed ("Eugene" with "Edmund" – in real life, Eugene was the third (youngest) child, who corresponds to the character of "Edmund" in the play); and O'Neill's mother, in real life Mary Ellen "Ella" Quinlan, is renamed to Mary Cavan. The ages are all the actual ages of the O'Neill family in August 1912.
In real life, Eugene O'Neill's father, James O'Neill, was a promising young actor in his youth, as was the father in the play, and did share the stage with Edwin Booth, who is mentioned in the play. He achieved commercial success in the title role of Dumas' The Count of Monte Cristo. Playing the title role about 6,000 times, he was criticized as "selling out" for commercial success at the expense of artistic merit.
Eugene's mother Mary did attend a Catholic school in the Midwest, Saint Mary's College, of Notre Dame, Indiana. Subsequent to the date when the play is set (1912), but prior to the play's writing (1941–42), Eugene's older brother Jamie did drink himself to death (c. 1923).
As to Eugene himself, by 1912 he had attended a renowned university (Princeton), spent several years at sea, and suffered from depression and alcoholism, and did contribute to the local newspaper, the New London Telegraph, writing poetry as well as reporting. He did go to a sanatorium in 1912–13 due to suffering from tuberculosis (consumption), whereupon he devoted himself to playwriting. The events in the play are thus set immediately prior to Eugene beginning his career in earnest.