Julian is a curious and highly empathetic young boy whose perspective shapes the stories. He possesses a vivid imagination that often blurs the line between truth and fiction, leading to playful mischief. Over the course of the book, his daily experiences teach him practical lessons about growth, honesty, and forming connections with others.

Huey is Julian's younger brother, characterized by his enthusiastic and trusting nature. As the younger sibling, he frequently looks up to Julian and becomes swept up in his brother's imaginative schemes. His gullibility and subsequent reactions often serve as a catalyst for Julian's realization of consequences.

Ralph is Julian and Huey's father, described as a big, warm man whose laughter lights up a room. He serves as a comforting and stabilizing presence in the household. He approaches parenting creatively, often indulging his children's imaginations to teach them practical lessons about responsibility and patience.

Mom acts as a wise, sensible, and stabilizing force within the family. Though she appears less frequently than Ralph, her interventions are critical, providing empathy and practical wisdom. She often helps reframe her children's insecurities, acting as an equal parenting partner rather than a stereotypical caregiver.

Gloria is a young girl who becomes Julian's new neighbor. Confident, adventurous, and physically coordinated, she challenges Julian's initial reservations about making female friends. Her proactive nature and belief in the magic of shared wishes make her a catalyst for Julian's social development.