Matt is a 12-year-old English colonist from Massachusetts who remains alone in the Maine woods for several weeks while his father fetches the rest of the family. He is resourceful and determined but initially lacks the specific skills needed to survive in the deep forest. Over time, he develops resilience, humility, and a deep appreciation for the Indigenous people who live nearby.

Attean is a 14-year-old boy from the Beaver clan of the Penobscot Nation. Proud, skilled, and deeply knowledgeable about the forest, he harbors strong resentment toward European colonists due to a tragic family history. He is forced by his grandfather to take English reading lessons from Matt, an arrangement he initially resents but which slowly exposes him to new ideas.

Saknis is the elderly leader of the Beaver clan and the grandfather of Attean and Marie. He is wise, compassionate, and forward-thinking, recognizing that his people need to understand the colonists' language to read future treaties. He initiates the arrangement for Matt to teach Attean English in exchange for food and survival lessons.

Grandmother is the matriarch of Attean's family and the wife of Saknis. She is described as a gaunt, handsome, and impressive woman who holds significant authority within her village. She harbors a deep, justified hatred for European colonists due to past violence against her family and initially refuses to welcome Matt into her home.

Marie is Attean's capable and methodical sister. Having been baptized by a Catholic priest when she was younger, she carries a European name. She plays a crucial role in mediating between Matt and her formidable grandmother during a moment of crisis regarding Attean's dog.

The Hallowells consist of Matt's father, mother, and sister, Sarah. They hail from Quincy, Massachusetts, and are the driving motivation for Matt's dedication to guarding the new Maine cabin. Their delayed arrival forces Matt into his prolonged wilderness survival situation.

Aremus is Attean's mangy, aggressive, and battle-scarred dog. Though he lacks the discipline to be a good hunting companion, he is deeply loved by his owner. The dog initially avoids Matt but becomes a central figure in testing the boy's bravery and compassion when caught in a trap.

Ben is a heavyset, transient colonist who claims to be a war hero on the run from trouble in a nearby town. He takes advantage of Matt's hospitality by begging for a meal and sleeping in the cabin, serving as a harsh reminder that fellow colonists can pose a serious threat to Matt's safety.