John, nicknamed "Crash" since he tackled his cousin as a toddler, is a hyper-competitive seventh-grade fullback. He struggles with his parents' long working hours and channels his frustration into physical aggression toward his peers. He covers his insecurities with deep arrogance, relying strictly on his athletic prowess to command attention and respect at school.

Penn is a nonviolent Quaker boy who lives in a converted garage with his older parents. He cherishes simple possessions like a pet turtle and a tin of river mud rather than television or expensive toys. He meets hostility with unshakeable kindness, genuinely attempting to befriend his aggressive neighbors.

Scooter is Crash and Abby's maternal grandfather, a former Navy cook who moves into their home. He provides the meals, supervision, and attention that the children miss from their busy parents. He transforms the guest room into a safe space, entertaining his grandchildren with adventurous tales from his time at sea.

Abby is Crash's eleven-year-old sister, characterized by her spirited nature and passion for wildlife. She protests her family's materialistic lifestyle, often clashing with her father over her plans to build a backyard animal habitat. She channels her desire for parental attention into loud environmental activism.

Mr. and Mrs. Webb are artists and devout Quakers who raise their son with nonviolent, vegetarian principles. They live simply, prioritizing family time and educational outings over television and modern conveniences. They regularly offer kindness and dinner invitations to Crash despite his obvious disdain for their lifestyle.

Jane is a transfer student who quickly gains popularity for her looks but refuses to tolerate arrogant behavior from the school athletes. She outright rejects Crash's aggressive flirtation and instead aligns herself with the school's social outcasts. She joins the cheerleading squad and supports protests against a local mall development.

Mike is a lineman on the middle school football team who shares Crash's hyper-competitive attitude. He acts as a primary instigator, escalating the practical jokes and mean-spirited pranks directed at peers. He places heavy value on expensive athletic gear and social dominance within the middle school hierarchy.

Crash and Abby's parents are deeply invested in their careers—Mr. Coogan running a business and Mrs. Coogan selling real estate. They provide financially for their family but routinely miss football games, family dinners, and milestones. Their constant exhaustion leaves their children to largely parent themselves.

Henry is Penn's 93-year-old great-grandfather, an elderly man who holds deep historical importance to his family. He ran in the famous Penn Relays during his youth, inspiring his great-grandson's name and athletic aspirations. He travels from North Dakota to Pennsylvania to watch the track events.

Bridget is Crash's cousin who suffered his physical aggression when they were small children. She remains wary of him years later, actively avoiding him at family holiday gatherings and rolling her eyes at his behavior.

Uncle Herm is Crash's uncle and Bridget's father. He organizes the family touch-football games during holiday gatherings and playfully recalls his nephew's early aggressive tendencies without recognizing the genuine harm they caused.

Eric is a defensive back on the seventh-grade football team. He participates in the roughhousing and aggressive locker-room culture that characterizes the middle school athletes before practices.