The film follows an insurance clerk (Lemmon) who, in hopes of climbing the corporate ladder, allows his superiors to use his Upper West Side apartment to conduct their extramarital affairs.

The Apartment was distributed by United Artists to widespread critical acclaim and was a commercial success, despite controversy owing to its subject matter.

To climb the corporate ladder, he allows four company managers to take turns borrowing his Upper West Side apartment for their extramarital affairs.

During the company's raucous Christmas Eve party, Sheldrake's secretary, Miss Olsen, tells Fran that her boss has had numerous affairs with other female employees, including herself.

Fran confronts Sheldrake at Baxter's apartment; he claims he loves her, but heads back to his family in White Plains.

Fran spends two days recuperating in Baxter's apartment, during which a bond develops between them, especially after he confesses to an earlier suicide attempt over unrequited love.

The initial concept was inspired by Brief Encounter by Noël Coward, in which Laura Jesson (Celia Johnson) meets Alec Harvey (Trevor Howard) for a thwarted tryst in his friend's apartment.

[5] Another element of the plot was based on the experience of one of Diamond's friends, who returned home after breaking up with his girlfriend to find that she had committed suicide in his bed.

[citation needed] Although Wilder generally required his actors to adhere exactly to the script, he allowed Lemmon to improvise in two scenes.

In one scene, he squirts a bottle of nasal spray across the room, and in another, he sings while cooking spaghetti (which he strains through the grid of a tennis racket).

[citation needed] Art director Alexandre Trauner used forced perspective to create the set of a large insurance company office.

[15] Esquire critic Dwight Macdonald gave the film a poor review,[14] calling it "a paradigm of corny avantgardism".

[16] Others took issue with the film's controversial depictions of infidelity and adultery,[14] with critic Hollis Alpert of the Saturday Review dismissing it as "a dirty fairy tale".

[11] MacMurray, having generally played guileless characters, related that after the film's release he was accosted by women in the street who berated him for making a "dirty filthy movie", and one of them hit him with her purse.

Since The Apartment only two black-and-white movies have won the Academy Award for Best Picture: Schindler's List (1993) and The Artist (2011) (Oppenheimer was in partial black and white).

In 1994, The Apartment was deemed "culturally, historically, or aesthetically significant" by the United States Library of Congress and selected for preservation in the National Film Registry.

Starring Jerry Orbach, Jill O'Hara and Edward Winter in the roles of Chuck, Fran and Sheldrake, the production closed in 1972.

An all-star revival began in 2010 with Sean Hayes, Kristin Chenoweth and Tony Goldwyn as the three leads; this version added the Bacharach-David compositions "I Say a Little Prayer" and "A House Is Not a Home" to the roster.