''Long Day's Journey Into Night'' is the story of a day in the life of a [[AwLookTheyReallyDoLoveEachOther loving]] but [[DysfunctionalFamily dysfunctional]] Irish-American family as it is torn apart by [[FatalFlaw addiction, resentment, and regret.]] It is also Creator/EugeneONeill's most autobiographical play, hence his insistence that it not be published until after his death. Winner of the 1957 Pulitzer Prize. Creator/FredricMarch won a Tony Award for his performance in the original Broadway production.

A well-regarded film adaptation, directed by Creator/SidneyLumet and starring Creator/KatharineHepburn as Mary, was made in 1962.

!!This play provides examples of:
* AuthorAvatar: O'Neill spent a great deal of his early adulthood at sea, battled with alcoholism and depression, and suffered from tuberculosis, just like Edmund.
* TheDiseaseThatShallNotBeNamed: Literally. Edmund tries not to speak about his illness, as he believes it could be his mother's final breaking point.
* DownerEnding: It is implied that the end scene has been and will be repeated many, many more times.
* DrFeelgood: The doctor who first prescribed Mary Tyrone morphine, as well as the doctors who continue to do so while she's OffTheWagon.
* ExtremelyShortTimespan: The play takes place between morning and midnight on a single August day in 1912.
%%* FatalFlaw: See above.
%%"See above" is not context. Do not uncomment this example without expanding it to stand on its own.
* GenerationXerox: Perhaps one of the morals of the play, sad as it may be.
%%* IgnoredEpiphany
%%Do not uncomment this example without expanding it to explain how it applies.
* IncurableCoughOfDeath: [[spoiler:Actually Tuberculosis.]]
* LampshadeHanging: "What a bastard to have for a father! Christ, if you put him in a book, no one would believe it!"
* TheOphelia: Mary, especially in the last scene. Mostly due to the [[spoiler:morphine]].
-->'''James''': The mad scene. Enter Ophelia!
* ParentsAsPeople: Mary and James are depressingly human.
* ShoutOut: Edmund compares himself to a [[Theatre/TheSeagull seagull.]]
* ShoutOutToShakespeare: Too many to count; the Tyrones are a family of actors, after all.
* WomanInWhite: Mary and her wedding dress.