How does Sam Spade in The Maltese Falcon represent a noir hero?

Sam Spade, as portrayed by Humphrey Bogart in the 1941 film adaptation of The Maltese Falcon, serves as the quintessential hard-boiled noir hero. He embodies the genre's core characteristics through his moral ambiguity, fatalistic outlook, and alienation from society.1

Spade is defined by a "compassionless pragmatism" rather than traditional altruism. While he avenges his partner’s murder, his motivation is rooted in a professional code—the belief that it is "bad business" to let a killer go—rather than deep emotional attachment. This detachment is a hallmark of the noir protagonist, whose ethics are often governed by a personal code rather than concern for others.1

Furthermore, Spade functions as an antihero who navigates a world of duplicitous characters, such as the femme fatale Brigid O’Shaughnessy. His ultimate decision to turn O’Shaughnessy over to the police demonstrates his adherence to his own uncorrupt, albeit cold, moral framework, solidifying his status as the archetype for subsequent hard-boiled detectives.23