Simon is a 17-year-old junior at Creekwood High School, the protagonist and central narrator of the novel. He is described as having messy hair, gray eyes, glasses, and as being “cute” (230). Simon is a generally well-adjusted teenager with a strong circle of friends, a loving family, and extracurricular activities and school communities he cares about. At the beginning of the novel, he has a secret email correspondent, Blue, with whom he exchanges anonymous emails about the experience of being a closeted gay teenager at their high school, among other topics. The rest of Simon’s friends and family do not realize he is gay, and he struggles with how to come out to them, even though he thinks in most cases they will be supportive. Over time, his emails with Blue become more romantic and sexual in nature, and Simon’s feelings for Blue become strong, although he has never met him in person.

Because he keeps secrets in the novel, Simon is required to be somewhat guarded about his personal life, often handling his feelings through the music he listens to. However, he also shows a natural tendency to want to be open about his feelings with those he loves.