Castle "Ghost" Cranshaw
Castle, who nicknames himself "Ghost," is the protagonist and narrator of the novel. At twelve, Castle is a middle-schooler living in the impoverished Glass Manor neighborhood of an unnamed city. Three years before the events of the novel, Castle's father went to prison for shooting at Castle and his mother as they fled their house. This episode taught Castle that he could run fast despite having no formal training as a sprinter. Fond of eating sunflower seeds, Castle has a tight bond with Mr. Charles, the man who runs the local convenience store. Traumatized by his father's abuse and alcoholism, Castle sleeps in the living room near his mother so he can be close enough to protect her. Castle has a "rap sheet" of getting into fights at school. He also impulsively steals a pair of running shoes when he finds that his regular high-tops are unsuited to his level of athleticism. Over the course of the novel, we see Castle begin to shift out of his dysfunctional ways as he learns the importance of discipline, humility, honesty, and camaraderie as a member of the Defenders track team.
Coach Otis Brody
Coach Brody is a former Olympic gold-medal runner who now coaches the Defenders and drives a cab. Coach Brody takes an interest in developing Castle's track skills when he sees how fast Castle runs against Lu. Hoping to instill discipline in Castle, the coach makes sure Castle does his homework every day while he drives him home after track practice. The coach is also tough on Castle during practice, pushing him to his physical limit to teach Castle the importance of humility. Later in the novel, the coach reveals to Castle that he grew up on the same block as him. Like Castle, the coach had to deal with the adversity of having a father who was an abusive addict. When the coach discovers that Castle stole his silver running shoes from Everything Sports, he punishes Castle by making him clean out his cab and by apologizing to the salesperson he deceived. However, Coach Brody pays for the shoes himself and lets Castle keep running in them.
Mr. Charles
Mr. Charles runs the "country store" where Castle buys sunflower seeds. Resembling a white version of James Brown, Mr. Charles is hard of hearing and fond of old cowboy films. Castle and Mr. Charles build a rapport, repeating the same exchange every day for Castle's one-dollar bag of sunflower seeds. When Castle and his mother are running from Castle's father, they take refuge in Mr. Charles's storage room. Later in the book, Castle finds himself trapped in the storage room and has a panic attack. Mr. Charles takes an active interest in Castle's life, building his ego when it comes to his athletic ability and expressing concern when Castle is skipping school.
Ma
Ma is Castle's mother. Raising Castle alone because his father is in prison, Ma works in a hospital cafeteria from which she brings home extra food for her and Castle to eat for dinner. In her time off, Ma studies to become a nurse, though she often procrastinates by watching romance films. After her husband's attempting shooting of her and Castle, Ma sleeps in the living room with Castle. Although Ma is suspicious of Coach Brody at first and worries about whether Castle can keep up with homework while training, Ma lets Castle join the track team. At the end of the book, Ma tears up when she sees Castle take part in his first track meet.
Brandon Simmons
Brandon is a student at Castle's school. A bully, Brandon routinely mocks Castle's poverty and neighborhood. One day during lunch, Castle punches Brandon in the face, which results in a one-day suspension for Castle and a longer suspension for Brandon. At the end of the novel, Castle must race against Brandon, who turns out to be a sprinter on a competing team.
Castle's Father
Castle's father is incarcerated during the novel's present-day storyline. An alcoholic with violent tendencies, Castle's father went to prison after firing a handgun in Castle's and his mother's direction when they were leaving the house. Castle says this traumatic event taught him he could run fast. Castle remembers how his father was fond of eating sunflower seeds, a habit Castle inherited.
Lu
Lu is a fellow "newbie" sprinter on Castle's track team. While watching the team practice, Castle grows frustrated with Lu's cocky attitude. Despite not being on the team, Castle challenges Lu to a race; it finishes too close to call and impresses Coach Brody enough that he invites Castle to join the team. Lu's and Castle's animosity gradually turns into mutual respect, and Lu encourages Castle when they compete alongside each other at the first track meet. Lu's appearance is notable to Castle because he has albinism, a condition that results in a lack of pigment in the skin, making him appear to Castle to be a white person with Black features. Because of his albinism, Lu was also nicknamed "Ghost." During the newbie dinner, Lu says he wishes he had a brother so he would know what he would look like without albinism.
Aunt Sophie
Aunt Sophie is Castle's mother's sister. Castle and his mother spend almost every weekend visiting with Sophie and her young son. During Castle's first track meet, Sophie boisterously calls out encouragement from the stands.
Tia
Tia is a salesperson at Everything Sports. Tia finds Castle a pair of silver running shoes in his size for him to try on. When she is busy with another customer, Castle steals the shoes. Later in the novel, Coach Brody makes Castle apologize to Tia for stealing the shoes and she forgives him.
Patty
Patina "Patty" Jones is a "newbie" middle-distance runner on Castle's track team. When Castle trips and falls during an early race against Lu, Patty consoles Castle. During the newbie dinner trust exercise, Patty confides that a white woman adopted her after Patty's biological mother had both feet amputated because of diabetes complications. Castle seems to have a crush on Patty, who is kind to him and openly comments on his good looks.
