A Moon for the Misbegotten, first produced in 1947, was penned by O'Neill as a tribute to his brother, Jamie, who is portrayed as Jamie Tyrone in the play. Similar to his character in Long Day's Journey into Night, Jamie is depicted as an alcoholic seeking comfort from various women. The narrative centers on his ill-fated romance with Josie Hogan. O'Neill eventually grew to despise this play, possibly due to the tragic suicide of his own son, which echoed his brother's fate.

Trouble in the Flesh (1959) is Max Wylie's vivid fictional portrayal of Seton Farrier, a character whose life as a leading dramatist is evidently inspired by O'Neill's own biography.

East of Eden (1952), John Steinbeck's epic tale of the Trask family, explores themes similar to those in Long Day's Journey into Night. Drawing from the biblical story of Cain and Abel, the novel delves into family corruption, sibling rivalry, jealousy, guilt, and the quest for forgiveness.

Death of a Salesman (1949), Arthur Miller's renowned "tragedy of the common man," shares thematic elements with O'Neill's work, such as the disastrous effects of materialism and the estrangement between fathers and sons. Miller's play is often considered the main contender to Long Day's Journey into Night for the title of America's greatest tragedy.

Buried Child (1978), Sam Shepard's mythic examination of a dysfunctional family burdened with guilt over the murder of a possibly real or imagined child, mirrors themes found in O'Neill's Long Day's Journey into Night, particularly in its retrospective storytelling approach.

A Hatful of Rain (1955), Michael V. Gazzo's play about the effects of a veteran's drug addiction on his wife, father, and brother, shares thematic similarities with O'Neill's work. The excellent 1957 film adaptation earned Anthony Franciosa an Academy Award nomination for Best Actor.