Theo Decker is a regular twelve-year-old boy. He is well-dressed and cared for, reflecting his mother’s attentive and elegant influence. He already possesses his observant blue eyes, they are bright and clear rather than weary. Having recently been abandoned by his alcoholic, gambling father, Theo carries an underlying anxiety about stability. He is highly sensitive to changes in his environment and dreads disappointing his mother. He is a smart, observant boy who enjoys school, reading, and exploring the city. He has a budding appreciation for beautiful things, fostered by his mother's love for art and history. Despite the stress of his parents' split, Theo still retains the core innocence, trust, and vulnerability of a protected child before his world is permanently shattered. He is friends with Andy and Tom.

Audrey is described as extraordinarily beautiful, but with a unique, non-traditional look. She has pale skin, a scattering of freckles, and striking, dark, almond-shaped eyes that give her a slightly exotic or sweeping appearance. She is famous for her heavy, dark hair, which she often wears pinned up or framing her face in an elegant, effortless way.She possesses a natural, classic sense of fashion. She wears tailored trench coats, simple sweaters, and clean lines. Audrey has a magnetic personality. She has a "charmed theatrical light" over everything, making the world seem brighter, sharper, and more saturated whenever she is around. she possesses a love for beauty, history, and literature. She views the world through a deeply creative lens and instills this profound appreciation for art in Theo. She is not a rigid or overly strict parent. She is whimsical and spontaneous.

Andy Barbour is scrawny, sickly, and physically weak. He is highly sensitive to his environment, lactose intolerant, and chronically plagued by severe allergies. He has a twitchy, physically awkward demeanor. Unlike his preppy, athletic, and outdoorsy family, Andy is completely non-physical. He looks entirely out of place next to his elegant mother, Samantha Barbour, and his handsome older brother, Platt, or Kitsy his younger sister. Andy is incredibly smart and academically advanced. He skipped a grade early in school, which originally bonded him with Theo. He has a somewhat "robotic" and clinical manner of speaking. Because of his poor social skills and fragile nature, he is chronically picked on and severely bullied by his peers—including his own brother. He feels that his mother favors Platt and his father favors his sister, Kitsey. Despite his robotic exterior, Andy has a heart of pure gold.