Even those critics who were unimpressed with the film were united in their praise of Jack Nicholson’s performance as Detective Jake Gittes. The character’s cynicism, world-weariness, and slightly sleazy disposition and habits were drawn straight from classic film noir detectives and the novels that inspired those films. Unlike the constant, cool self-assurance of Humphrey Bogart’s Sam Spade in the celebrated film noir The Maltese Falcon, Nicholson plays Gittes as a man in over his head.

In fact, much of Jake’s anger and determination come from his frustrated realization of just how lost he truly is. Nicholson made the infamous bandage, a disfigurement many actors wouldn’t have risked, into a steadying force for Jake. The violence of the knife attack is something he can at least understand and respond to appropriately. Nicholson has a very human approach to the role, the pinnacle of which is his decision to imbue Jake with a stubborn optimism and sense of decency that survive despite his profession and his prior experience in Chinatown. His actions in the final scene are startling and powerfully effective, leaving the viewer with affection for Jake despite his baser tendencies.

Faye Dunaway’s portrayal of Evelyn Mulwray is firmly rooted in the film noir tradition of mysterious and beautiful heroines, though the character departs from the femme fatale model. Most of her actions and dialogue are designed to let Nicholson’s character know that she is hiding something from him. Dunaway, however, adds surprising shadings to simple lines. Rather than rely on the distance of cool calculation, Dunaway makes Evelyn’s reticence that of pure fear: she is a bad liar in a dangerous situation whose only hope of not saying something dangerous is to say nothing at all. Though she continues in the film noir tradition of sleeping with the detective, the oddly tender scene beforehand makes it clear that the sex is the mutual seduction of two lonely people. The discussion of Jake’s past that immediately follows is a quest for emotional intimacy that neatly bookends the moment. Dunaway’s portrayal suggests that Evelyn hopes to have found a kindred spirit in Jake. The occasional quaver of her voice and the fragile desperation with which she asks him to come back with her hint at a woman who believes she is just as lost as Jake has become.

John Huston’s portrayal of Noah Cross is the film’s most electrifying performance. He has less screen time than Nicholson and Dunaway, but he still succeeds in giving his character depth. Noah Cross appears to be a faultlessly personable and charming man, a characterization that sets Huston’s interpretation of villainy apart from traditional screen villains. Huston’s care to keep his pleasantly wrinkled face and friendly smile unmarred by any shades of baser intent makes Cross’s character all the more sinister to viewers as they discover his inherently evil nature. How can someone do what Cross has done, believe the things Cross believes, and still look so innocent? What depth of psychosis does that require? Huston’s genius is that the viewer’s imagination eclipses an entire film’s worth of character analysis, turning a character with a mere handful of scenes into a nightmare incarnate.