When Jean-Pierre Melville brought a copy of the script to Alain Delon, Delon asked him what the title was. When he was told the title was "Le samouraï", Delon had Melville follow him to his bedroom, where there was only a leather couch and a samurai blade hanging on the wall. Melville had written the screenplay with Delon expressly in mind for the lead.
Jean-Pierre Melville worried how he was going to shoot the scene where Jef drives the stolen car right into the scrap garage. Without missing a beat, Alain Delon drove the car down the narrow alley and into the garage in one shot.
According to Rui Nogueira (author of the book "Melville on Melville" published in 1976), the caged bird shown as Jef Costello's pet in the film was the only casualty of the fire that destroyed Jean-Pierre Melville's studio in 1967.
This is one of the most influential films in history. Martin Scorsese, Quentin Tarantino, Francis Ford Coppola, Jim Jarmusch, John Woo, Johnnie To, David Fincher, Bernardo Bertolucci, Aki Kaurismäki, Takeshi Kitano, Georges Lautner, Nicolas Winding Refn, Luc Besson, Joel Coen, Ethan Coen, and others have all made films inspired by it.
The start of the film is completely dialog-free for nearly ten minutes. The first word, "Jef?", is spoken by Jane Lagrange (Nathalie Delon).