The most important characters in the novel are Julie herself and the wolves— four adults and five puppies—who serve as her companions on the tundra. Her father, Kapugen, is present for the most part only in her imagination; through most of the story she believes him to be dead. The other human characters— Daniel, the mentally disabled boy to whom she is married, and her stepmother, Martha—are minor characters whom she leaves behind.

Julie is a thirteen-year-old Eskimo girl. Her mother died when she was very young, and her father, Kapugen, overwhelmed by grief, left the village, taking his little daughter with him into the wilderness. There he taught her the old Eskimo way of life. Kapugen's lessons become the key to Julie's survival on the tundra. She is patient, intelligent, observant, and self-reliant. Although she is frightened by being lost, she pushes away her fear and husbands her resources, both material and spiritual.

Amaroq (the word means "wolf" in the Eskimo language) is a royal black wolf and the leader of the pack that Julie befriends. Fearless of enemies and protective of his family, Amaroq becomes, in Julie's imagination, almost a surrogate father figure. The other adults in the pack are Amaroq's beautiful mate Silver, who is loving and respectful; Nails, a gray wolf; and Jello, the villain of the piece and low dog in the pack. Jello babysits the pups while the other adults go off to hunt, and is the last to eat when they return home. Eventually he is exiled, but as a loner he becomes dangerous, attacking Julie's camp and then Julie herself for her food.

He had talked to her not with his voice, but with his ears, eyes, and lips; and he had even commended her with a wag of his tail.
The five puppies are playful creatures, childlike in their behavior. Kapu (for Kapugen) is their leader and Julie's favorite. He is fearless and intelligent, and becomes the pack's leader when Amaroq is killed by hunters. Kapu is the first wolf with whom Julie establishes a friendly relationship.

Julie of the Wolves is filled with details about both wolf behavior and the natural history of the tundra. Although untrained, Julie observes the world around her like a scientist. Her experience and observations give credibility to the major underlying theme of the book—that human beings are only one small part of a vast ecological system. Failure to recognize humankind's unity with nature is seen as dangerous and destructive; litter, airplanes, guns, oil rigs, and the gadgetry of modern life— these represent the imposition of the human will on the natural world.

The disparity between civilization and nature seems clear when Julie is lost on the tundra. A far more ambivalent relationship emerges when Julie enters Kangik and finds that Kapugen, who in her imagination represents the pure Eskimo ideal, has compromised and adopted modern ways. She finds that he even hunts wolves in an airplane, raising the possibility that Kapugen himself might have shot Amaroq.

Julie is confused by these compromises, and by her father's assertion that the old ways are dying. She rebels at his suggestion that perfect harmony between humans and the natural world is no longer possible. But by the end of the book Julie recognizes that she too must adapt to survive in a new kind of wilderness—that of an ecologically responsible modern civilization.