Jay Gatsby is the titular character of F. Scott Fitzgerald's 1925 novel The Great Gatsby. The character has become an archetype of self-made American men seeking to join high society, and the name has become synonymous with successful businessmen with shady pasts in the US, dealing with prohibition.
James Gatz, a bright young man from a poor family in North Dakota, despises the imprecations of poverty so much he drops out of St. Olaf College in Minnesota after only a few weeks because he is ashamed of working as a janitor in order to pay his way. Renaming himself Jay Gatsby, he learns the ways of the wealthy while working for a copper tycoon named Dan Cody, but upon Cody's death is cheated out of a $25,000 bequest by Cody's mistress. While training in 1917 to join the infantry and fight in World War I he meets and promptly falls in love with a beautiful young woman named Daisy, who represents everything he is not: she is rich, and she is from a patrician East Coast family.
During the war he reaches the rank of Major, commands the heavy machine guns of his regiment, and is decorated "for valour" for his participation in the bloody battles of Marne and Argonne. After the war, he supposedly attends Trinity College, Oxford, but he lies throughout the story that he did. While there he receives a letter from Daisy telling him she has married the equally aristocratic Tom Buchanan. Rather than admit defeat, he commits his life to becoming a man of the sort of wealth and stature he imagines could win her love.
Gatsby returned home to an America transformed by prohibition in 1919, a period in American history in which gangsters earned the sort of vast wealth previously the domain of the connected upper classes, an era in which "all the old boundaries that separated the classes were being broken, and a new wave of instant millionaires, like Gatsby himself... mingled with the polo-players who inhabited the stiff enclaves of the established rich of Long Island's gold coast." This era later came to be known as the Jazz Age, after Fitzgerald's own coinage.
Gatz made a fortune in bootlegging thanks to his association with gangsters like Meyer Wolfsheim (patterned after real-life American gangster Arnold Rothstein). With his income Gatsby set himself up in a mansion in the fictional West Egg, Long Island, a haunt of the nouveau riche. This is across an inlet from the old-line money East Egg, where Daisy and Tom Buchanan live. Despite being a bootlegger, Gatsby never drinks (while working on Dan Cody's yacht, he witnessed Cody almost fall overboard in a drunken stupor). Every weekend, Gatsby hosts parties open to all comers, in the hopes that Daisy will attend and he can win her heart. He eventually catches up with Daisy, but fails to convince her to leave Tom. After his failure to change Daisy's mind is clear to all but him, Daisy drives Gatsby's car with Gatsby in the passenger seat and she accidentally strikes and kills Myrtle, the lover of her husband Tom, in a hit-and-run accident. Myrtle's jealous husband Wilson tracks the car back to the Buchanan home, where Tom tells him that Gatsby was the owner of the car that killed his wife. Wilson goes to Gatsby's house and murders him, before taking his own life. Only one of Gatsby's high society friends attends his funeral, accompanied by his father and Nick Carraway, the story's narrator and Gatsby's only real friend.