Thomas "Tom" Buchanan is the main antagonist of F. Scott Fitzgerald's 1925 novel The Great Gatsby and all of its subsequent adaptations. He represents the corruption and elitism of "old money" and pre-Depression social stratification. He is Jay Gatsby’s archenemy.
Tom is a very vain, pompous, and egotistical individual who would use his great wealth to escape consequences because of his actions. He also was extremely uncharitable and callous with other people, such as when Myrtle gets struck and killed by Daisy as the latter drove Gatsby's car, he clearly disregarded Daisy being held responsible for Myrtle's death and instead had Gatsby to blame; even though he cared for her death as he visibly seen crying and unwilling to admit the truth.
He was also shown to be very hypocritical, sanctimonious, manipulative and unreliable; when Tom discovered that his wife was having an affair, he was infuriated never mind the fact that he was doing the exact same thing. To make matters worse, he also had xenophobic tendencies as he believed that he was a part of a Caucasian race called the Nordics, and it was their duty to suppress the non-white, inferior races before they overthrew the Nordic race. Tom would exploit other people without any remorse to the point where he caused two men to be killed (one to be shot and the other committing suicide) even though it was shown that Gatsby's dreams were in shambles and that he would never get Daisy.
Tom Buchanan was the husband of Daisy Fay and also the father of a young girl. He was noted as being very arrogant and brutish, and had no qualms with destroying other people's lives just as long as it benefited him.
When Nick Carraway, the narrator, decided to visit his distant cousin Daisy and see what the East was like, he immediately noticed that Tom was having a not-so subtle affair on his wife. Tom then takes him into the city and makes him get off and see his mistress, whose name was Myrtle, the married wife to George Wilson the owner of the gas station. Later on, he breaks Myrtle's nose while at a party after she repeatedly said Daisy's name much to his chagrin.
Tom also grew very suspicious with Jay Gatsby and with how he knew his wife. When he was suspecting that she was having an affair with him, he did some searching around and discovered that Gatsby was secretly a bootlegger, and he uses this fact against Gatsby when he, Daisy, Gatsby, and Jordan were at the Plaza Hotel. When Gatsby firmly stated that Daisy would leave him, he laughs it off, stating that she would never leave him. When she said she was, he quickly exasperated reminding her of the things that only they knew of in secrecy. Daisy then leaves because she couldn't take all the arguing. She drives Gatsby's car, and runs over Mrs. Wilson. When Tom learns that Myrtle had been run over, he convinces a grief-stricken George that Gatsby was the one who murdered his wife causing George to plot revenge on him.
The next day, Wilson then walks to Gatsby's residence and shoots him while he was floating on a mattress in his swimming pool. When Nick confronted Tom about his friend's murder, Tom admits that he had to tell Wilson that Gatsby killed his wife in order to save his own life. He felt no remorse for causing two men to die (Wilson shot himself after killing Gatsby) and stated that Gatsby got what was coming to him since he claimed Gatsby was driving the murder car. Nick then leaves in disgust, and returns to the West.
Buchanan was shown to have parallels with William Mitchell, the Chicagoan who in real life married Ginevra King (the former lover of the book's author F. Scott Fitzgerald and also the inspiration for Daisy Buchanan).