The focus of Wilson's attention in Fences is Troy, a 53-year-old working-class head of household who struggles with providing for his family. The play takes place in Pittsburgh, Pennsylvania; although never officially named, it makes mention of several key locations in Pittsburgh. In his younger days, Troy was an excellent player in Negro league baseball and continued practicing baseball while serving time in prison for a murder he had committed during a robbery. Because the color barrier had not yet been broken in Major League Baseball, Troy was unable to get into the MLB to make good money or to save for the future. He now lives a menial, though respectable, blue-collar life of trash collecting; later in the play, he remarkably crosses the race barrier and becomes the first black truck driver in Pittsburgh instead of just a barrel lifter.
Troy lives with his wife, Rose, his teenage son, Cory, and his younger brother Gabe, an ex-soldier whose war injury to his head has caused him noticeable psychological damage. Gabe had received $3000 from the government, and Troy took control of this money to purchase a home for his family, including a room for Gabe. A short time before the play's opening, Gabriel has rented a room elsewhere, but still in the neighborhood. Lyons is Troy's older son from a previous marriage, and lives outside the home. Bono is Troy's best friend and co-worker.
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; 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, who is a rigid believer in hard work and responsibility, belittles his son because he refuses to find a real job as Troy did rather than pursuing his dream of becoming a musician.
Cory tells Troy and Rose about an opportunity for a college football scholarship. Troy tells Cory he will not let his son play football for fear of racial discrimination, just as Troy believes he experienced when he wanted a career in the National leagues. However, it is suggested later on that Troy told Cory's coach that his son is no longer to play football. When Cory discovers this, he and Troy get into a fight resulting in Troy sending Cory to his room. Later, it is revealed that Troy's age after serving a prison sentence, not his race, may have been the primary factor. Father and son argue about Troy's actions, but Troy stubbornly does not back down from his argument and kicks Cory out of the house. Later it is revealed that Cory enlisted in the military after this event.
Troy admits to Rose that he has been having an affair and that his mistress, Alberta, is pregnant. Later, Alberta dies in childbirth. Troy brings his baby daughter Raynell home, and Rose agrees to raise the girl as her own, saying: "From right now . . . this child got a mother. But you a womanless man." She remains in the family home but the couple are estranged; she refuses to accept Troy back into her life.
Seven years later, Troy has died. Cory comes home for a visit from the military where he is a corporal in the Marines. He initially refuses to go to his father's funeral due to long-standing resentment, but he 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 family say their farewells to Troy and offer forgiveness that may not be fully deserved.
The brother Gabriel is potentially an allegory to salvation. Other than being actually named Gabriel, like the angel, Gabe wears a trumpet, constantly chases away unseen "hellhounds", and regularly believes himself to be speaking with Saint Peter. At the end, just before Troy's funeral, the family gathers around Gabe in the yard. He blows three times into his trumpet, but no sound comes out. In a moment of trance, Gabe begins to dance and sing. The sun breaks through the clouds while the family looks on. Troy is at last delivered and the rest of the family is too; each seeming to find peace in their relationship with Troy.
The fence referred to by the play's title is built over many years and is revealed to be finished only in the final act of the play. It is not obvious as to 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. The fence is also symbolic of the emotional barrier that Troy erected between himself and his sons, one from each of his adult relationships. Rose also wanted Troy to build the fence as a symbolic means of securing what was her own, keeping what belonged inside in (her family), and making what should stay outside, stay out.