Daisy and Tom Buchanan's young daughter, Pammy plays a very minor role in the novel as a possession meant to be displayed. She is always dressed like her mother and represents the shallowness of her parents. Daisy herself hopes that Pammy will grow up to be a "beautiful fool."

Dan Cody is Jay Gatsby's best friend and the man responsible for who Gatsby eventually becomes. Cody employs Gatsby for five years, and Nick's observations indicate that Cody drank too much and likely participated in criminal activities. Given their history and that the twenty-five thousand dollars Cody left to Gatsby when he died were never received, it's possible Gatsby turned to crime in order to make his own fortune.

Henry Gatz is Jay Gatsby's father. Despite being poor, he is dignified and immensely proud of his son. He remains ignorant of Jay's bootlegging and underground connections, only believing his son to have been a great man.

Mr. Klipspringer lives off Jay Gatsby's wealth by boarding in his mansion and rarely contributes beyond playing the piano for Daisy and Gatsby. Nick perceives Klipspringer to be a friend of Gatsby’s, observing how Gatsby compliments Klipspringer for the music he plays. However, after Gatsby’s death Klipspringer reveals himself to be just as shallow as the rest of Gatsby’s associates, only dwelling in Gatsby's home to take advantage of his lush and extravagant lifestyle.

The minor character Owl Eyes provides a subtle commentary on the vanity of the Long Island elites and reveals aspects of Jay Gatsby’s character. He notes how remarkable it is that the books in Gatsby’s library are real. This comment not only implies the insincerity of “the secret society,” who are superficial and lack substance, but also confirms Gatsby’s character, who has a greater degree of integrity. However, the pages of the volumes have not been cut apart, revealing that while Gatsby aspires to a life of meaning and authenticity, he remains in denial, refusing to face life’s difficult truths.

George Wilson is married to Myrtle and is one of the primary victims of the Buchanan’s recklessness. George represents the common people victimized by the carelessness and cruelty of the extraordinarily wealthy. He is poor, earns just enough money to get by, and has to ask Tom Buchanan, the man having an affair with Myrtle, for a car so he can move away. After Daisy Buchanan accidentally kills Myrtle in a hit and run, George descends into a destructive spiral of grief. Seeing his grief as an opportunity, Tom tells George that it was Jay Gatsby who had both seduced and killed Myrtle. This causes George to murder Gatsby.

Myrtle Wilson is Tom Buchanan’s mistress and George Wilson’s wife. Since Tom and George stand at opposite ends of the socioeconomic spectrum, Myrtle represents the lower classes’ desire for social advancement. Her relationship with Tom is less about love and more about the appearance of wealth and desirability she earns through him. However, her fixation on status and appearances means that she is unable to fight back against Tom’s abuse. Myrtle is so obsessed with material gain that she is willing to prioritize it over her own well-being, which ultimately results in her death when she is struck and killed by a speeding car she believes belongs to Tom. In the end, her life and death exemplify the abuses suffered by the poor at the hands of the wealthy.

A selfish and insecure man, Meyer Wolfsheim is one of Jay Gatsby's associates in the criminal underworld. He is a mobster who focuses on bootlegging and racketeering. For Nick, Wolfsheim serves as a window into the clandestine part of Gatsby's life because their association clarifies how Gatsby acquired his wealth. However, Nick separates Gatsby and Wolfsheim based on character. Whereas Gatsby cares about others, such as Daisy, Wolfsheim is insensitive and selfish. He even refuses to attend Gatsby’s funeral, claiming that he cannot let such a scandal interfere with his own business interests. Based on his characteristics, Wolfsheim is considered a fictionalized version of Arnold Rothstein, a racketeer and mob kingpin in New York City who was shot to death in 1928.

Myrtle Wilson's sister, Catherine is proud of Myrtle's connection to the wealthy Tom Buchanan, and she is unconcerned with the questionable morality surrounding the affair.

Michaelis is a young Greek man who owns a coffee shop next door to George and Myrtle Wilson. After Myrtle is struck and killed by a car, Michaelis is the chief witness to the events.

Mr. and Mrs. Mckee live in the apartment below the one that Tom rents for his dalliances with Myrtle. They attend gatherings at Tom and Myrtle’s flat. Mrs. Mckee is a shrill and “horrible” woman who incessantly flatters Myrtle, believing her to be of the upper classes. Mr. Mckee is a photographer and he tries to use Nick Carraway's and Tom Buchanan's elevated statuses to gain access to the more affluent artistic circles.

Mr. Sloane is a friend of Tom’s who stops by Gatsby’s house while horseback riding with a young woman and Tom. The young woman accompanying Mr. Sloane invites Gatsby over to dinner and Gatsby accepts, not realizing that the invitation was extended as a formality. In order to re-establish the social order, Sloane departs before Gatsby is finished getting ready. This scene, and Sloane’s surprise over Gatsby’s acceptance of the invitation, serves as a reminder that even though Gatsby is wealthy, he does not have the upper-class upbringing of Tom, Daisy, and Sloane.