Twenty-six year old Travis Bickle applies for a job as a New York City taxicab driver. The personnel officer drills Travis with questions, and warms to him when he realizes they both served in the Marines. After Travis expresses his willingness to drive long hours, any day, in any part of the city, he is hired. Travis later writes in his diary about the poor condition of the city, the disturbing people he sees, and his new job which pays him $300 to $350 per week. At work, he picks up an older man with a prostitute and complains afterward about cleaning bodily fluids off the backseat of the cab. After working twelve hour shifts, he complains that he cannot sleep and wants a purpose in life. One day, Travis sees a campaign worker named Betsy and describes his romantic impression of her in his diary. Inside headquarters for Senator Charles Palantine’s presidential campaign, Betsy and her coworker, Tom, engage in friendly conversation while Travis watches from his parked cab. Betsy becomes aware of Travis; however, when Tom goes outside to confront him, he speeds away. Later, he sits with fellow cab drivers in an all-night cafeteria, and they discuss the various acts of violence they've encountered. Travis remains distant and glares at several African American men. Sometime later, Travis asks Betsy out for coffee, and she accepts. At a diner, Travis and Betsy discuss the campaign, and she offers her impression of Travis, comparing him to lines from a song by Kris Kristofferson. Travis promptly buys the record. One evening, Travis picks up Senator Palantine. Though ignorant about political issues, Travis suggests the candidate clean up the city and expresses his support of the senator's candidacy. Later, a twelve year-old prostitute, Iris, gets into Travis' cab. No sooner is she in the cab, when her pimp, Matthew, also known as “Sport,” arrives and pulls her from the car. Travis takes Betsy to a pornographic movie on their next date. She becomes agitated, storms out of the theater, and hails a cab. After numerous attempts to send her flowers, Travis calls Betsy in an attempt to reconcile, but she has no interest. As time passes, Travis grows angrier. He rushes into Palantine’s campaign office, yells at Betsy, and threatens her. One evening, a passenger instructs Travis to pull over so he can watch the shadow of a woman standing by a lit window in an apartment building. The passenger explains that she is his wife and is having an affair. He tells Travis he intends to kill her. Travis listens, occasionally glancing suspiciously at the passenger in the rearview mirror. Later, at the cafeteria, Travis confides to Wizard, an older driver, that he has been having destructive thoughts. Wizard tells Travis to stop worrying and promises he will be okay. One night, Travis almost hits Iris by accident. He follows her and a friend as they walk down the street, but the girls pick up two men on the corner. Travis discusses loneliness in his diary, and states that his life needs a change. He meets with Easy Andy who sells, among other things, guns. Travis purchases an assortment of firearms and, intent on getting into shape, begins working out, eating healthier, and taking target practice. At home, he practices pulling guns out of holsters and hiding a knife in his boot. One day, Travis attends a rally for Palantine where he talks with a secret service agent who appears suspicious of his behavior. As Travis walks away, agents try to snap a picture of him, but he disappears into the crowd. At night, Travis stops at a convenience store. When a young man holds up the cashier, Travis approaches from the back of the store and shoots the thief. He then panics because he doesn't have a gun permit, but the cashier promises to cover for him and sends him away. After he leaves, the cashier beats the unconscious criminal with a metal bar. Travis watches another campaign event from his cab, but police usher him away. At home, he writes to his parents, telling them he has a top-secret government job and a girlfriend named Betsy. He later approaches Iris and arranges a deal for her services with Sport. They go into a nearby apartment building where Iris’ timekeeper charges Travis for a room and waits in the hallway. Inside the room, Iris seduces Travis, but he rejects her advances. He explains that he came because he wants to help her escape. The next day, they meet for breakfast at a diner. Travis tells Iris he may have to go away for work, and he wants to give her money so she can leave Sport and her life as a prostitute. In the evening, alone with Sport, Iris expresses her unhappiness, but he manipulates her into staying. After more target practice and preparation, Travis arrives at another rally, having shaved his hair into a Mohawk. Travis approaches Palantine, but, when he reaches into his coat, the secret service men see him and spring into action. Travis escapes to his apartment where he regroups and heads back out, this time to the apartment building where Sport operates. Travis shoots Sport and enters the nearby building where Iris sees clients. In the hallway, he shoots Iris’ timekeeper. Having followed Travis inside, the wounded Sport shoots him in the neck, but Travis returns fire and kills the pimp. He makes his way to Iris’ room as the timekeeper, still alive, comes after him. Travis is then shot by Iris’ client, but he quickly fires back and kills the man. The timekeeper attacks Travis as he crashes into Iris’ room. After a struggle, he stabs the timekeeper and shoots him in the head while Iris looks on, terrified. Travis attempts to shoot himself next, but the guns are out of bullets. He collapses on the couch moments before the police enter. In the days that follow, news reports praise Travis as a hero, and Iris' parents send him a thank you letter for bringing their daughter back to them. After recovering from the incident, Travis returns to work. One night, he picks up Betsy, and they awkwardly discuss Palantine's nomination victory and Travis' brush with fame. At her destination, Betsy gets out of the cab and Travis throws the meter, giving her a free ride.