The focus of Wilson's attention in Fences is Troy, a 53-year-old head of household who struggles with providing for his family. The location is never specified but seems to be Pittsburgh as there are several references to some of its notable institutions. Troy was a great baseball player in his younger years, having spent time practicing in prison for an accidental murder he had committed during a robbery. Because the color barrier had not yet been broken in Major League Baseball, Troy was unable to make good money or to save for the future. (However, one line of the book does cast some doubt as to whether it was Troy's age, not his skin color that kept him from becoming a professional baseball player). He now lives a menial, though respectable life of trash collecting—remarkably crossing the race barrier and becoming a driver instead of just a barrel lifter. He lives with his wife, Rose, his son Cory (who still lives in the house at the play's opening), and Troy's younger brother Gabriel, an ex-soldier whose war injury to his head has caused him noticeable psychological damage. Lyons is Troy's son from a previous marriage, and lives outside the home. Bono is Troy's best friend. Troy had taken Gabriel's money that he'd been entitled to for his injury, and bought the house he currently lives in. A short time before the play's opening, Gabriel has rented a room elsewhere, but still in the neighborhood.
The play begins on payday, with Troy and Bono drinking and talking. Troy's character is revealed through his speech about how he went up to their boss, Mr. Rand, and asked why black men are not allowed to drive garbage trucks (Troy works as a garbage man); Rose and Lyons join in the conversation. Lyons, a musician, has come to borrow money from Troy, confident that he will receive it and promises to pay him back because his girlfriend Bonnie just got a job. Troy gives his son a hard time, but eventually gives him the requested ten dollars after Rose persuades him to do so. About mid-play, an affair between Troy and a woman named Alberta (who is never seen in the play) is revealed, followed by the discovery that Alberta is pregnant. Cory tells Troy and Rose about an opportunity for a college football scholarship. Troy tells Cory he won't let his son play football in fear of racial discrimination, like that Troy experienced while playing professional baseball. Troy and Cory argue about Troy's actions but Troy stubbornly does not back down from his argument and sends Cory to his room. Later on it is discovered that Troy told Cory's coach that his son is no longer to play football. With Cory's discovery of this, he and Troy get into a fight resulting in Troy's kicking Cory out of his house. Troy gets a call concerning Alberta's pregnancy. She dies during childbirth. Rose agrees to adopt the baby girl, Raynell, and take care of the baby as her own, though she no longer considers herself to be Troy's woman. Seven years later, Troy has died. During this final act, Raynell, the daughter conceived in Troy's union with Alberta, is seen as a happy seven-year-old; Cory comes home from military training. He initially refuses to go to his father's funeral due to long-standing resentment, but is convinced by his mother to pay his respects to his father—the man who, though hard-headed and often poor at demonstrating affection, nevertheless loved his son.
The fence referred to by the play's title is revealed to be finished in the final act of the play, and Bono has bought his wife a refrigerator as he promised Troy he would do if he finished building it. It is not immediately known why Troy wants to build it, but a dramatic monologue in the second act shows how he conceptualizes it as an allegory—to keep the Grim Reaper away. Rose also wanted to build the fence and forced her husband to start it as a means of securing what was her own, keeping what belonged inside in and making what should stay outside stay out.