Sam is a fifteen-year-old skater with aspirations to attend art college. Raised by a mother who had him at sixteen, he carries a lingering sense of guilt over his family's history and wants to be the first person in his family to finish school. He relies heavily on a poster of professional skateboarder Tony Hawk, reciting quotes from Hawk's autobiography to calm his anxieties about adult responsibilities.

Alicia is a teenager from a wealthy family who lives in a large, old house. She prefers staying in her bedroom to watch television rather than attending her parents' social events. When faced with life-altering news, she demonstrates unexpected directness and a willingness to confront difficult situations head-on.

Sam's mother is a young parent who had Sam when she was only sixteen years old. She attempts to build a personal life by dating a man named Mark while working and raising her son. Her own history makes her hyper-aware of the risks her son faces, causing her to be highly protective and sometimes easily embarrassed by her past.

Robert is Alicia's father. He lives in a large home and places high expectations on his daughter's future. He forms immediate negative assumptions about Sam based on his working-class, young-parent background, viewing early parenthood as a disaster that must be prevented.

Andrea is Alicia's mother. She holds strict prejudices against teenage parents and expects her daughter to live a conventional life. She openly disapproves of Sam's background and treats his mother with thinly veiled condescension during social events.

Sam's father is largely absent from his son's daily routine following a lengthy divorce. He tells graphic stories about the day Sam was born while eating cake at Sam's birthday celebration. Despite his physical distance from the family, he possesses practical experience regarding the harsh realities of young relationships.

Rabbit is a skilled skateboarder who practices at a local park called the Bowl. He calculates Sam's mother's age aloud and frequently asks whether she is single. His carefree attitude represents the simple teenage life Sam is accustomed to.

Rubbish practices skateboarding at Grind City and the Bowl with his friends. He struggles to complete tricks and frequently falls off his board to scrape his knees. He focuses entirely on learning new tricks and enjoying his youth.

Tony Hawk is a real-world professional skateboarder and author. He appears as a poster on Sam's bedroom wall, serving as an imaginary sounding board for Sam's fears. Sam visualizes him offering quotes from his autobiography when real life becomes overwhelming.

Mark is a man currently dating Sam's mother. He attempts to establish a friendly rapport with Sam during their early meetings. He enters the family dynamic during a period of high stress and tries to be accommodating.