Molly and Alice Miller The Judge's daughters, whom Buck protects when they go on long walks.
Manuel A Mexican; one of the Judge's gardener's helpers. Because of his mounting gambling debts, Manuel steals Buck and sells him to a ring of dognappers.
The Man in the Red Sweater An unnamed person whom Buck remembers for the rest of his life because this is the person who teaches Buck the lesson that "a man with a club was a lawgiver, a master to be obeyed."
Perrault and François Two Frenchmen who are Buck's first new masters. They work for the Canadian government, delivering dispatches to outposts throughout the frozen North.