Turner is the 13-year-old son of a minister who recently relocated from Boston to Phippsburg. He feels stifled by the strict expectations placed on him by his father and the conservative townspeople. Uncomfortable in his stiff white shirts and isolated from his peers, he longs for the freedom of the western territories.

Lizzie is a 13-year-old Black girl living on Malaga Island, an impoverished community just offshore from Phippsburg. She possesses a confident, free-spirited nature that immediately draws Turner's attention. Despite the harsh realities of local prejudice and her family's difficult circumstances, she maintains a lively and authentic presence.

Reverend Buckminster is the new pastor of Phippsburg's First Congregationalist church and Turner's father. He attempts to secure his family's position in the new town by rigidly enforcing social norms. He feels intense pressure from the wealthy members of his congregation to support their business interests over his own moral compass.

Mr. Stonecrop is a wealthy businessman and a leading figure in Phippsburg. He aggressively pushes a plan to evict the residents of Malaga Island to build a tourist resort. He uses his influence and financial power to force the local church and its new minister into supporting his profitable scheme.

Mrs. Cobb is an elderly resident of Phippsburg who lives across the street from Mrs. Hurd. She strictly enforces the town's conservative standards and takes offense at any improper behavior. Her sharp demands result in Turner being assigned to read to her every day as a punishment.

Willis is the son of Deacon Hurd and a local boy in Phippsburg. He is arrogant and immediately antagonistic toward Turner. He capitalizes on the newcomer's unfamiliarity with local customs and fully participates in the town's harsh judgment of outsiders.

Mrs. Hurd is an older resident of Phippsburg who stands apart from the town's rigid conformity. She paints her shutters yellow and her door red, directly contrasting with the standard green used by her neighbors. She offers Turner sympathy and practical advice when he faces trouble with other boys.

Deacon Hurd is a leader in the First Congregationalist church and a prominent figure in Phippsburg. He allies himself with wealthy businessmen to enforce the town's strict social hierarchies. He prioritizes financial prosperity and community conformity over empathy.

Reverend Griffin is a preacher and the respected leader of the Malaga Island community. He attempts to protect his people by maintaining a quiet dignity in the face of aggression from the mainland. He uses the island's cemetery as proof of his community's historical right to their home.

Mrs. Buckminster is Turner's mother and the wife of the new town minister. She tries to maintain peace within her family as they adjust to the harsh judgments of their new community. She occasionally speaks up to defend her son when her husband's strictness becomes overbearing.

Sheriff Elwell is the local law enforcement officer in Phippsburg. He serves the interests of the wealthy white businessmen in town. He uses intimidation and physical threats to force the residents of Malaga Island from their homes.