Noah is a realistic high school junior who hides his passion for writing and creating visual art. Having accepted his lack of athletic talent, he plans to quit trying out for the baseball team. He harbors a deep, unrequited crush on his lifelong friend Sam but lacks the confidence to confess his feelings directly.

Walt is Noah's relentlessly optimistic best friend who approaches life with a carpe diem attitude and a philosophy he calls "hug life." Despite lacking athletic talent, he practices batting tirelessly. He holds a deep passion for jazz music, using its rhythms and history as motivation for achieving his goals.

Sam is a high school junior who has been close friends with Noah and Walt since elementary school. She dates the school's star baseball player, Cruz. Kind and trusting, she frequently turns to Noah for support and conversation, completely unaware of the depth of his romantic feelings for her.

Moses "Mo" Jones is Walt's older brother, currently serving in the US military in Afghanistan. Named after Moses Fleetwood Walker, the first African American Major League Baseball player, Mo represents an idol of coolness and athletic achievement to his younger brother.

Floyd is Walt's older cousin who produces a podcast called the "Woohoo Woman." He shares Walt's deep love for jazz music and speaks in a poetic, cryptic manner that confuses Noah but deeply inspires Walt. He views himself as an expert on romance.

Cruz is the confident star player of the high school baseball team. He commands attention and popularity, representing the athletic success that eludes Noah and Walt. He dates Sam, though he struggles to understand her personal preferences and boundaries.

Divya is a confident thrift store employee who immediately catches Walt's attention. She shares his intense passion for jazz music and vintage records, sparking an instant connection between them when she offers him a Miles Davis album.

Corinthian is the author of five elegant, poetic love letters from the past. Though he does not appear in person, his articulate and heartfelt writing provides Noah with the inspiration to express his own feelings through art.

Annemarie is the woman to whom Corinthian addressed his heartfelt love letters. Like Corinthian, she exists in the story only through the historical artifacts found in the vintage purse.

Noah's mother is a caring parent who sets firm house rules before leaving for an overseas conference. She receives a vintage Louis Vuitton purse from Noah for her birthday, which inadvertently holds a secret stash of old letters.

Noah's father prepares to travel to Barcelona for a conference. Before leaving, he presents Noah with a refurbished truck that once belonged to Noah's grandmother, offering driving instructions.