Jeremiah is Conrad’s younger brother. Jeremiah follows in Conrad's footsteps, joining the football team at school and deciding to work as a lifeguard at the country club because Conrad had planned to do the same. He also develops feelings for Belly. 

Jeremiah and Belly grow closer the summer she’s thirteen. One afternoon, they overheard their mothers discussing Susannah’s cancer and her concerns about having a mastectomy to remove one of her breasts. Confronted with the raw reality of cancer, the two young people realize the seriousness of Susannah’s condition. Their bond deepens in that moment, and Belly grows closer to Jeremiah than she is with her own brother, Steven. Toward the end of the summer, Jeremiah reveals to Belly that he wants to be more than friends. However, he realizes he can’t compete with his older brother for her affection. 

Although Jeremiah has a happy-go-lucky exterior, he can be very sensitive. He’s deeply hurt by the realization that Belly’s feelings for Conrad will always be stronger than her attraction to him. He also struggles to cope with his mother’s illness. Unlike his brother Conrad, who compartmentalizes his emotions and withdraws from others, Jeremiah is unable to hide his pain.