Hank Grotowski, a widower, and his son, Sonny, are corrections officers in a Georgia prison. They reside with Hank's father, Buck, a bigoted retired corrections officer whose wife (Hank's mother) committed suicide. Sonny is friends with the Cooper brothers, Willie and Darryl, who are black. At the behest of Buck, Hank frightens off the brothers with a shotgun and is later confronted by their father Ryrus.
Hank, the prison's deputy warden, will oversee the execution of convicted murderer Lawrence Musgrove. Musgrove, a talented amateur artist, draws a sketch of Sonny. Sonny is a shy and gentle person, and is as kind to Musgrove as his duties permit.
The night before the execution, Hank tells Sonny that a "monster's ball" is held by the corrections officers, a get-together of those who will participate in the execution. The proceedings prove too much for Sonny, who, as he is leading Lawrence to the electric chair, vomits, and then collapses. Following the execution, Hank confronts Sonny in the prison's bathroom and slaps him for being so "soft" and "ruining a man's last walk".
The next morning, Hank attacks Sonny in his bed and orders him to leave the house. Sonny grabs a revolver from under his pillow and holds his father at gunpoint. The confrontation ends in their living room with Hank sitting on the carpet, and Sonny in Buck's customary chair. Sonny asks his father if he hates him. After his father calmly confirms that he does, and always has, Sonny responds, "Well, I always loved you," and commits suicide by shooting himself in the chest.
A devastated Hank buries Sonny in the back garden with an abbreviated funeral because, as Buck comments, "He was weak." Hank subsequently resigns as deputy warden, burns his uniform in the backyard, and locks the door of Sonny's room. He purchases a local gas station in an attempt to provide a distraction in his retirement. The Coopers offer condolences to Hank, who asks which one is Willie and which one is "Harry" (mistaking Darryl's name) and is corrected politely.
During the years of Lawrence's imprisonment leading up to his execution, his wife, Leticia, has been struggling while raising their son, Tyrell, who has inherited his father's artistic talent. Overwhelmed, she lashes out at the boy for his obesity, resorting to physical and emotional abuse. Along with her domestic problems, Leticia struggles financially, with an eviction notice on her house from her landlord. In desperate need of money, Leticia takes a job at a diner frequented by Hank. Due to lack of maintenance (which Lawrence had suggested) the car breaks down, so Leticia and Tyrell begin walking back and forth between home and the diner.
One rainy night, Leticia (having stolen an umbrella) and Tyrell are walking down a soaked highway. Hank happens to be driving along and sees Tyrell lying mortally wounded on the ground and Leticia calling for help. After some hesitation, Hank stops, and being told Tyrell was struck by a car, he drives them to a hospital, where Tyrell dies from his injuries. At the suggestion of the authorities at the hospital, Hank drives Leticia home. A few days later, Hank gives Leticia another ride home from the diner. They begin talking in the car about their common losses, and she invites him in. Hank finds out that Leticia is Lawrence's widow, though he does not tell her that he participated in her husband's execution. They drown their grief with alcohol and have sex.[8]
Hank takes Sonny's old truck to Ryrus' auto shop and they discuss fixing it, with Hank mentioning he wanted to sell the truck, and asking if Ryrus' boys could wax it. He then offers to give the truck to Leticia, who reluctantly accepts after initial protests of discomfort.
Leticia stops by Hank's home with a present for him, but he is not there. She meets Buck, who insults her and implies that Hank is only involved with her because he enjoys sex with black women. Leticia, offended by the remarks, refuses to interact with Hank. After Hank is made aware of Buck's actions, he commits his father to a nursing home. He then renames the gas station "Leticia's", saying it is his girlfriend's name when asked.
Leticia is evicted from her home and Hank invites her to move in with him. She later discovers Hank's involvement in her husband's death when she finds the drawings of Sonny and Hank done by Lawrence as he awaited execution. She’s disturbed by the revelation, but numb from the loss of her son and recent misfortune, she’s waiting for Hank when he returns from town with ice cream. The film ends with the two of them eating ice cream together on the back porch, content with each other as Hank states that he thinks they’ll be okay.
Billy Bob Thornton as Hank Grotowski
Halle Berry as Leticia Musgrove
Heath Ledger as Sonny Grotowski
Peter Boyle as Buck Grotowski
Coronji Calhoun as Tyrell Musgrove
Sean Combs as Lawrence Musgrove
Mos Def as Ryrus Cooper
Charles Cowan Jr. as Willie Cooper
Taylor LaGrange as Darryl Cooper