J.J. (Jake) Gittes
The protagonist of the film, Jake Gittes is a private investigator with a reputation for going to great lengths for his clients. Depicted as morally ambiguous, thus fitting the mold of a neo-noir lead character, Jake is driven to uncover the truth, even if it means being deceitful and aggressive during his investigations. Fiercely defensive of his work, Jake believes it is his duty to help desperate people in need. Jake has a tendency to jump to conclusions that aren't necessarily accurate, but sharing his rash conclusions with others usually helps him get closer to the truth. Jake also shows a masterful ability to turn on his charm to gain access to sources before quickly switching from polite to accusatory. While his work usually involves collecting evidence against cheating spouses, Jake becomes obsessed with discovering why someone hired a woman to pose as Evelyn Mulwray. As the conspiracy case becomes increasingly complicated, Jake develops romantic feelings toward Evelyn, which compromises his judgment during the investigation. Jake carries the burden of a traumatic episode from his past as an employee of the District Attorney in Chinatown; without telling Evelyn exactly what happened, Jake intimates that he became romantically involved with a woman he tried to protect, and his effort to help the woman accidentally ensured harm came to her. While Jake believes he can simultaneously protect Evelyn while proving her father's guilt in Hollis Mulwray's murder, Jake's intervention brings about Evelyn's death, an eerie repeat of his traumatic past.
Evelyn Mulwray
Evelyn Mulwray is the mysterious and elegant wife of Hollis Mulwray; she is also Noah Cross's daughter. Refined and withdrawn, Evelyn is the "femme fatale" archetype of the film, meaning she is an attractive woman likely to cause distress to the man who becomes involved with her. Evelyn is often reticent with Jake, who is simultaneously drawn to her and irritated by her evasiveness. As the film progresses, Jake suspects Evelyn of having been involved in her husband's murder; however, it turns out that Evelyn hasn't been forthcoming with the truth because she has been hiding the fact she was impregnated by her father as a teenager and gave birth to a daughter, Katherine, in Mexico. Knowing her father is capable of great evil, Evelyn hopes to run away with Katherine to start anew and keep her away from Noah. At the end of the film, Evelyn shoots her father in the arm when he tries to get in her car with Katherine. As she drives away, a police officer's bullet hits Evelyn in the back of the head, leaving her dead on her steering wheel.
Noah Cross
Noah Cross is a wealthy landowner and gangster; he is also Evelyn and Katherine's father. Able to obscure his cruel nature with his folksy demeanor, Noah orchestrates a scheme that involves manufacturing a drought to build an unnecessary and structurally unsafe dam, pushing farmers off their land so he can buy it cheaply, and incorporating his ill-gotten land into the City of Los Angeles so he can sell it off for millions more. It also comes out that Noah impregnated his own daughter, Evelyn, when she was a teenager. Jake discovers that Noah murdered Hollis after Hollis learned Noah was manufacturing the drought. Although Jake uncovers the conspiracy, Noah's complicated web of corruption means he is unlikely to face scrutiny from the police. Noah is remorseless when Jake confronts him with his crimes, suggesting Noah is a sociopath who is liable to sexually abuse Katherine in the same way he abused Evelyn.
Hollis Mulwray
Hollis Mulwray is the chief engineer of the Los Angeles Department of Water and Power; he is also Evelyn's husband. A former business partner of Noah Cross, Hollis has a long-standing dispute with Noah over Noah's shady business practices and Hollis's belief that water should be a public utility. When Hollis discovers Noah is manufacturing a drought to shore up public support for a new dam project, Noah murders Hollis by drowning him in the salt-water pond in Hollis's backyard. While Jake believes in the opening scenes of the film that he has collected photographic evidence of Hollis cheating on Evelyn, Hollis is actually spending time with Evelyn's long-lost daughter Katherine, who he has brought up from Mexico so she and Evelyn can reunite.
Katherine
Katherine is the biological daughter of Evelyn Mulwray and Evelyn's father, Noah Cross. The child of incest, Katherine is both Evelyn's daughter and her half-sister. Born and raised in Mexico, Katherine speaks with an accent. Young, blonde, and innocent, she is depicted as an archetypical ingenue who likely does not know the full history of her origins. Jake photographs Hollis with Katherine and leaks the photos to the press, believing Katherine is his mistress. Evelyn initially goes along with the story, revealing later that she gave birth to Katherine when only fifteen, and Hollis took care of her until Evelyn was finally ready to see her. At the film's tragic climax, Katherine witnesses her mother die as they are trying to flee Noah, from whom Evelyn wants to protect Katherine. Katherine screams hysterically as Noah puts his arms around her and pulls her away from Evelyn's car.
Lou Escobar
Lou Escobar is a police lieutenant and former professional associate of Jake's. Escobar and Jake treat each other with familiarity and hostility when their paths cross at the Oak Pass Reservoir the day Hollis is found dead. When Escobar suspects Evelyn of murdering Hollis, Jake misdirects him in order to protect Evelyn. At the end of the film, Escobar's frustration with Jake leads him to dismiss Jake's claim that Hollis is behind the many recent mysterious deaths. After his partner shoots Evelyn as she flees, Escobar releases Jake from custody and angrily tells him to leave the crime scene.
Ida Sessions
Ida Sessions is a sex worker who impersonates Evelyn Mulwray in order to hire Jake to investigate Hollis's alleged affair. After Hollis's death is publicized in the media, Ida calls Jake to say that she didn't know her involvement in the stunt would result in anyone's death. Instead of revealing who hired her, Ida tells Jake to look in the obituaries section of the paper for a clue; Jake uses this tip to piece together Noah Cross's involvement in a broader conspiracy. Ida is later found dead in her home with Jake's phone number on her wall. Escobar has a detective phone Jake to get him to the scene of the crime.
Lawrence Walsh
Lawrence Walsh is an operative who works for Jake, collecting information on subjects Jake is investigating. Walsh is familiar with Jake's troubled history working for the DA in Chinatown. At the end of the film, Walsh pulls Jake away from the scene of Evelyn's crashed car and says: "Forget it, Jake. It's Chinatown." With this brief statement, Walsh communicates to Jake that, like the last time, there is nothing more he can do but walk away and carry the burden of his remorse.
Kahn
Kahn is Evelyn Mulwray's butler. Kahn is hostile toward Jake and protective of Evelyn and Katherine, who he looks after at a remote suburban house following Hollis's death. At the end of the film, Evelyn and Katherine seek refuge temporarily at Kahn's Chinatown home, outside of which Evelyn is shot dead.
Gardener
During his first visit to the Mulwrays' mansion, Jake observes a gardener fret over how the salt-water pond kills the surrounding lawn. Jake is unsure what the man is talking about when he says the pond is "bad for glass," but on a later visit, Jake realizes the man has a Japanese accent and is saying "grass." Upon learning the pond is full of salt water, Jake realizes Hollis was drowned in it and he makes a significant break in the case. At Jake's request, the gardener retrieves a broken pair of bifocals from the pond; the glasses turn out to belong to Noah Cross, Hollis's murderer.
