At 12 years old—though he turns 13 late in the novel—William is the eldest Pearce child and a main protagonist. He begins the novel as a classic archetype of a responsible eldest sibling. After their parents died, William took on the responsibility of parenting his younger siblings, Edmund and Anna.

William sees this as his duty. William takes on unpleasant tasks to protect his siblings and consistently tries to consider their futures. William urges his siblings, especially Edmund, to try and get along with the Forresters so that they may remain fed, clothed, and protected, if not respected or loved. Later, when he and Edmund are forced to catch and kill rats for money, William volunteers to kill two rats so Edmund does not have to. Though he subsequently gets violently ill, he tells Edmund “I’m glad you didn’t hit any. Nobody should have to do such a thing” (170).

The responsibility of parenting his younger siblings sits heavily on his shoulders and sometimes gets the better of him. Since he is the only sibling who remembers their parents, Anna often asks him for stories about them. Because the stories she asks for far exceed the memories he has, he often makes things up to comfort her.