The Big Sleep
Lundgren is Geiger's handsome lover. His favorite three words are, "Go — yourself," which he repeats incessantly, much to Marlowe's annoyance. Lundgren shoots and kills Brody, thinking that Brody had killed Geiger. He is also the one who had moved Geiger's body into his bedroom. Lundgren commemorates Geiger's body in a ritualistic way by lighting candles and placing two Chinese silk strips in a cross across Geiger's chest. Marlowe turns Lundgren into the police and Lundgren is charged with Brody's murder.
Brody is a small-time gangster who was once romantically involved with Carmen. General Sternwood paid him to stop seeing his daughter. In the past, Brody had successfully blackmailed Sternwood about Carmen, and this time Brody and his current girlfriend, Agnes Lozelle, attempt to blackmail Vivian with nude photos of her sister. In an effort to take over Geiger's porn racket, Brody had stolen the photos from Owen Taylor after tailing him from Geiger's house, but Marlowe's able to recover the photos from Brody by blackmailing him. Brody is shot and killed by Carol Lundgren, who was seeking revenge for the death of his lover, Geiger.
Taylor is the Sternwood's chauffeur. Marlowe learns that Taylor was in love with Carmen and tried to run away with her. However, Vivian pressed charges and Taylor got thrown in the clink. After his release, the Sternwood family still re-hires him. When Taylor realizes that Carmen is at the center of a blackmail scheme, he shoots and kills Geiger in an effort to protect Carmen. But the next morning, his body is discovered in the ocean after his car had driven off the pier. Taylor's head had been bashed in, but the police are unable to confirm whether his death was suicide or murder. And we never find out either.
Agnes Lozelle is the front-girl for Geiger's porn operations and Joe Brody's current girlfriend. She is attractive, but plenty shady and dangerous. She and Brody blackmail Vivian with naked photos of Carmen, but after Brody is killed, Agnes joins forces with Jones. After Jones is poisoned, Marlowe meets with Agnes to give her the $200 for information on Mona. Marlowe feels disgusted that Agnes is able to leave town unharmed when three men she was involved with are now dead (Geiger, Brody, and Jones).
Harry Jones is a small-time criminal who drives a gray Plymouth sedan. He's friends with Brody and Regan, and partners up with Agnes to blackmail Marlowe. Jones tails Marlowe for several days until Marlowe finally confronts him, and he offers to give Marlowe information about Mona Grant in exchange for $200.
That's probably why Marlowe takes a liking to Jones and describes him as a small man in a big man's world. Sadly, Jones is poisoned by Canino after telling him Agnes' address, but it turns out that he gave Canino a fake address. So in the end, even though Jones was involved in crime, he's still okay in Marlowe's book since he didn't rat out his partner. Jones' sense of loyalty fits right in with Marlowe's own personal code of being loyal to the client.
Canino is Eddie Mars' ruthless, trigger-happy hit man. He dresses all in brown and even drives a brown car. He poisons Harry Jones with cyanide after getting Agnes' address from him. Canino gets into a fight with Marlowe at the Art Huck's garage, where Mona Grant is hiding out. Canino knocks Marlowe out cold, but later, with the help of Mona, Marlowe shoots and kills Canino. We find out later from Vivian that she had paid Canino off for getting rid of Rusty Regan's body.
Terrance "Rusty" Regan
Rusty Regan is the husband of Vivian Sternwood. When the novel opens, we find out that Rusty disappeared several months earlier, having apparently run off with Eddie Mars' wife, Mona. As Marlowe untangles the mystery surrounding the Sternwood family, we eventually discover that Rusty never ran off with anyone. He was shot and killed by Carmen because he had rejected her sexual advances. His murder was covered up, and his body was buried in an oil sump.
That means we never get to meet him, since the poor guy was dead long before the novel ever began. But he remains an important character in that General Sternwood was extremely fond of Rusty, who used to have long conversations with him in the greenhouse. Marlowe is aware of the General's affection for Rusty, and since Marlowe himself has a soft spot for Sternwood, he makes all the more effort to find out what happened to Regan.
At the end of the novel, Marlowe contemplates Rusty's death and thinks that the only way to escape the sordidness of everyday reality is through death. So even though Rusty isn't even a real character in the sense that he's, well, dead, he represents the idea that death puts everyone on the same level, from the rich to the poor, the corrupt to the upright.
Ohls is the chief investigator for Wilde and, for the most part, a pretty good guy. He's friends with Marlowe and had recommended Marlowe to General Sternwood. Like Marlowe, Ohls takes pride in his work. He informs Marlowe about Owen Taylor's death, and goes with Marlowe to report the murders of Brody and Geiger.
Captain Cronjager works for the police department. He is at Taggart Wilde's house when Marlowe and Ohls stop by to report Geiger's and Brody's murders. Cronjager chews Marlowe out for not reporting the deaths earlier, and the two get into a heated argument. Chandler presents a clear rivalry between the police force and the private detective. When Marlowe reads the newspaper accounts of the two murders, he finds out that Cronjager gets all the credit for solving the case, and that Marlowe's name is never even mentioned once.
Captain Al Gregory
Captain Gregory is in charge of the Missing Persons Bureau. Marlowe senses that Gregory knows more than he lets on. In a touching conversation with Marlowe late in the novel, Gregory says that he tries to be an honest man in a dishonest world, but that justice isn't possible in this country anymore. Gregory provides Marlowe with a photo of Regan and the backstory of his involvement with the Sternwood family.
Norris is the Sternwoods' butler and holds a considerable amount of power in the household since he's the one who writes out checks for the General. At the end of the novel, Vivian reveals to Marlowe that Norris knew that Carmen had killed Rusty. Vivian says that Norris would never say anything, and Marlowe responds that he had a feeling Norris had known all along.
Wilde is the District Attorney. He is connected to the Sternwood family because his father was a close friend of the General's.