Sugar is a 10-year-old Black girl who formerly lived enslaved at River Road. Now orphaned after her mother's death and father's sale, she is raised by surrogate grandparents. She despises the harsh labor of cutting cane and the lingering smell of sweat and dirt. Highly curious and adventurous, she frequently breaks rules to explore the Mississippi River and seeks out friendships with people outside her social boundaries.

Billy is the youngest son of the white plantation owners at River Road. Unlike the workers, he is free to play and does not have to perform hard labor. He longs for adventure outside the plantation and builds a makeshift raft to sail the river. He shares Sugar's rebellious spirit, making them fast friends despite societal rules forbidding their association.

Beau is the youngest of the Chinese men hired to work the sugarcane fields. He arrives wearing traditional billowy clothing and a single braid. He is dignified, patient, and quick to form a connection with Sugar, whom he sees as a younger sister figure. He shares his culture through animal stories, a Chinese finger trap, and food, helping bridge the gap between the different groups on the plantation.

Mister Beale is an elderly Black man and the respected leader of the River Road workers. Captured in Africa as a child, he now struggles with failing eyesight caused by cataracts but maintains a strong spirit. He is a gentle surrogate grandfather to Sugar, entertaining the community with traditional Br'er Rabbit trickster tales.

Missus Beale is an older Black woman who serves as Sugar's surrogate grandmother. She is a strict disciplinarian who frequently scolds Sugar for her mischievous behavior, assigning her chores like soap-making. Beneath her tough, irritable exterior, she feels a deep sense of responsibility for Sugar and serves as a gifted cook for the community.

Mister Wills is the owner of River Road plantation and the former enslaver of its Black workers. He struggles to adapt to the post-emancipation economy as younger workers flee north, prompting him to hire Chinese immigrants to harvest the cane. He strictly enforces racial segregation but slowly learns that the survival of his farm requires a willing, cooperative workforce.

Tom has been the overseer at River Road plantation for two decades. He is deeply prejudiced, violent, and refuses to accept the new realities of post-emancipation labor. Armed with a whip and a gun, he uses intimidation to maintain control and actively resents any improvements in the workers' conditions or moments of cross-cultural unity.

Missus Wills is the lady of the house at River Road and Billy's overprotective mother. She strictly adheres to the social hierarchies of the era and prefers a tidy, predictable life. She is deeply uncomfortable with any mixing between the races and tries to keep her son away from the plantation's brutal realities.

Master Liu is the wise, respected elder and leader of the Chinese workers. He saved his men from starvation in their home country and guided them across the ocean to America. Like Mister Beale, he is a gifted storyteller who uses traditional tales about dragons and the Chinese zodiac to impart wisdom to the younger generation.

Initially known simply as "No Name," Jade is a black-and-white stray cat that wanders the plantation. Free to roam without following rules, he becomes a cherished companion to Sugar, who eventually names him after a figure in one of Beau's traditional Chinese stories.

Lizzie is Sugar's childhood best friend and the only other child among the Black workers at River Road. She adheres strictly to the social rules separating Black and white people, disapproving of Sugar's secret interactions with Billy before she and her parents leave the plantation to move north.

Sugar's deceased mother who passed away on New Year's Day two years prior to the story. She worked through a severe fever during harvest to avoid losing her season's pay. Her final instruction to her daughter was to "Do. See. Feel" and survive.

Sugar's father who was sold away from the River Road plantation during the Civil War. His absence leaves Sugar clinging to the hope that he might one day return for her.

The preacher's wife at River Road plantation. She is an active member of the Black worker community who distributes sweets during the harvest celebration and participates in communal meals.

The preacher for the Black workers at River Road. He leads community prayers, announces the arrival of the new workers, and presides over cemetery visits.

A wagon driver hired to transport the Chinese workers from the ship to River Road. He draws the ire of both the workers and Mister Wills when he delivers the men in ankle chains.

A Chinese worker who has a long scar across his eye from a childhood rock-throwing incident. He forms a friendly connection with Sugar when he shows her a photograph of his family.

Billy's older brother who has left River Road to attend school in New Orleans. He co-built the rundown raft that Billy now uses on the Mississippi River.