Nick Carraway (narrator) — bond salesman from the Midwest, a Yale graduate, a World War I veteran, and a resident of West Egg. He is Gatsby's next-door neighbor.
Jay Gatsby (originally James Gatz) — a young, mysterious millionaire later revealed to be a bootlegger, originally from North Dakota, with shady business connections and an obsessive love for Daisy Fay Buchanan, whom he had met when he was a young officer in World War I.
Daisy Buchanan née Fay—an attractive and effervescent, if shallow, young woman; Nick's second cousin, once removed; and the wife of Tom Buchanan. Daisy is believed to have been inspired by Fitzgerald's own youthful romance with Chicago heiress Ginevra King.
Tom Buchanan — millionaire who lives on East Egg, and Daisy's husband. Buchanan has parallels with William Mitchell, the Chicagoan who married Ginevra King. Buchanan and Mitchell were both Chicagoans with an interest in polo. Like Ginevra's father, whom Fitzgerald resented, Buchanan attended Yale and is a white supremacist.
Jordan Baker — She is Daisy Buchanan's long-time friend, a professional golfer with a slightly shady reputation. Fitzgerald told Maxwell Perkins that Jordan was based on the golfer Edith Cummings, a friend of Ginevra King. Her name is a play on the two then-popular automobile brands, The Jordan Motor Car Company and the Baker Motor Vehicle, alluding to Jordan's "fast" reputation and the freedom now presented to Americans, especially women, in the 1920s.
George B. Wilson — a mechanic and owner of a garage.
Myrtle Wilson — George Wilson's unstable wife and Tom Buchanan's mistress
Meyer Wolfsheim — a Jewish man Gatsby describes as a gambler who had fixed the World Series. Wolfsheim is a clear allusion to Arnold Rothstein, a New York crime kingpin who was notoriously blamed for the Black Sox Scandal which tainted the 1919 World Series.
Catherine — Myrtle Wilson's sister.
Chester and Lucille McKee — Myrtle's New York friends.
"Owl-eyes"—a drunken party-goer whom Nick meets in Gatsby's library. One of the few people to attend Gatsby's funeral.
Ewing "The Boarder" Klipspringer — a sponger who virtually lives at Gatsby's mansion.
Pammy Buchanan — the Buchanans' three-year-old daughter.
Henry C. Gatz — Gatsby's somewhat estranged father in Minnesota.
Michaelis — George Wilson's neighbor.
Dan Cody — a wealthy adventurer who was Gatsby's mentor as a youth.