Why is No Man of Her Own considered a film noir?

Mitchell Leisen’s 1950 film No Man of Her Own is categorized as a film noir due to its tense narrative and thematic elements characteristic of the genre.1

The film, an adaptation of William Irish’s novel I Married a Dead Man, centers on a protagonist who finds herself entangled in a web of blackmail after assuming a mistaken identity. This premise aligns with the conventions of film noir, which typically features intricate plots and cynical characters often found in post-World War II American crime dramas. While the genre is frequently defined by stark lighting, the use of flashbacks, and an underlying existentialist philosophy, No Man of Her Own specifically captures the noir spirit through its suspenseful exploration of deception and moral compromise.12