Jack is an eighteen-year-old young man working for a tourist ferry service in Sims Chapel, Tennessee, during the summer of 1950. Living with his widowed mother, he works hard to lift himself out of poverty, harboring dreams of becoming a novelist and buying a prominent house on a hill. He is modest, respectful, and earnest, possessing a strong belief that individuals can determine their own destinies through hard work.

Ellie is a freshman astronomy student from a wealthy family in Ohio, visiting her Aunt Clara in Tennessee for the summer. Driven by a desire to succeed in a male-dominated academic field, she faces high expectations from her demanding mother. Despite her privileged background, she quickly embraces the rural lifestyle of Sims Chapel, showing a witty and adventurous spirit.

Helen is Jack's practical, hardworking widowed mother. Having lost her husband and younger son, she struggles with grief but remains fiercely independent and dedicated to keeping a roof over her family's head. She encourages Jack's ambitions while trying to protect him from potential heartbreak.

Clara is Marie's sister and Ellie's aunt, living in the prominent house on the hill in Sims Chapel that Jack admires. She is a warm, generous, and beloved community figure who fell in love with the Tennessee lifestyle and stayed after her husband's death. She acts as a supportive maternal figure for Ellie during the summer.

Marie is Ellie and Amelia's mother, originally from Tennessee but now living a status-conscious life in an Ohio suburb. She is a strict, demanding figure who places immense pressure on Ellie to achieve academic and career success, often attempting to control her daughter's life from afar.

George is the seventy-five-year-old owner of the tourist ferry service on Douglas Lake where Jack works. Though he drinks heavily and holds a cynical view about class mobility, believing that people from humble backgrounds cannot rewrite their stars, he is a kind and generous mentor to Jack.

Sara is a local math major in Sims Chapel and one of Jack's oldest friends. She takes on the job of tutoring Ellie in algebra during the summer. Beneath her academic focus, she harbors romantic feelings for Jack and quickly displays jealousy as Jack and Ellie begin spending more time together.

Amelia is Ellie's sister, remaining at home in Ohio during the summer. She serves as a vital confidante for Ellie, keeping her secrets safe from their controlling mother and offering a sympathetic ear regarding Ellie's budding romance.

Lewis is Jack's deceased younger brother, who tragically drowned in a creek at the age of nine. Though he is no longer alive, his memory heavily influences Jack, who frequently addresses journal entries to him and visits his grave to seek solace.

Zora is a young woman originally from Mississippi who works alongside Ellie at Indiana University. She serves as a straightforward, practical colleague who frequently encourages Ellie to balance her professional dedication with a healthy personal life.

Michael, often called Mike, is a young man in Ellie's university social circle. Coming from a background similar to Ellie's, he presents himself as a suitor and views individuals outside his social class with skepticism and disdain.

Sam is the friendly owner of a bookstore frequented by university faculty and students in Bloomington. He takes great pride in his shop but faces difficult decisions about potentially selling his business to protect his wife's declining health.

Matthew is a dependable boat hand who works in the charter business on Douglas Lake. He helps manage an expanding fleet of boats and works closely with Jack on the water.

Trey is Zora's supportive partner. He relocates to Bloomington to support Zora's career opportunities at the university, prioritizing his relationship over geographic preferences.

Bill is Clara's deceased husband. Coming from a different social background than Clara's family, his marriage to her serves as an example of choosing love over societal expectations.

Caroline is Jack's adult daughter, who checks in on him and helps manage his affairs in his old age. She offers to accompany him on a difficult upcoming trip, showing concern for his well-being.