In the film Marion lives in Phoenix, Arizona as a secretary and is unhappy in her relationship with Sam Loomis (John Gavin), a divorcé who is in too much debt to marry her.

Marion rejects his idea to take the afternoon off and rushes back to her storefront real estate office.

Believing his mother has committed the murder, Norman puts the naked corpse and shower curtain—and, unknowingly, the money—in the trunk of Marion's car and sinks it in a nearby swamp.

In the novel, she is named Mary Crane, originates from Dallas, Texas, and dies after Norman decapitates her; in the film, "Mother" stabs her repeatedly.

The film introduces Mary Loomis (Meg Tilly), Lila's daughter with Sam and Marion's niece.

In the second sequel, 1986's Psycho III, the shower scene appears again in a flashback, this time when Norman sees Maureen Coyle (Diana Scarwid) who reminds him of Marion.

Later, after being rescued by Norman, "Mother" kills Maureen by pushing her down the same stairs of the Bates house where private investigator Milton Arbogast died.

Marion appears in the 1992 three-issue comic book adaptation of the 1960 film Psycho, released by Innovation Publishing.

In the TV series Bates Motel, a contemporary prequel to the 1960 film Psycho,[3] Marion is a notary public living in Seattle, Washington.

Marion rushes to her real estate office and asks her boss George Lowery for a promotion and a pay raise, but he refuses.

Rihanna portrayed Marion in the fifth and final season of the TV series Bates Motel, a contemporary prequel to the 1960 film Psycho.