Sister is the unnamed narrator and postmistress of the second-smallest post office in Mississippi. As the oldest sibling by exactly one year, she assumes the bulk of the domestic duties in her multigenerational household in China Grove. She feels constantly overlooked and put-upon by her family members, harboring deep-seated jealousy toward her younger sister. She seeks independence and external approval, though she struggles to see situations from any perspective other than her own.

Stella-Rondo is the narrator's younger sister, described by Sister as a spoiled woman who easily discards things she no longer wants. She recently separated from a photographer in Illinois and returns to Mississippi on the Fourth of July. Her sudden reappearance, along with an allegedly adopted blonde toddler, disrupts the household routine. She skillfully turns family members against one another to secure her position in the home.

Papa-Daddy is the maternal grandfather and patriarchal head of the household. He is an elderly, wealthy, and influential figure in China Grove who expects absolute reverence from his family. He proudly wears a long beard that he has been growing since he was fifteen years old. He regularly reminds the household of his political connections and uses his authority to demand compliance from his daughters and granddaughters.

Mama is the mother of Sister and Stella-Rondo. She tries to maintain an appearance of propriety and decorum in the face of her family's eccentricities. She quickly defends Stella-Rondo's claims about Shirley-T.'s adoption to avoid the social stigma associated with out-of-wedlock pregnancies. She often inserts herself into the sisters' conflicts, sometimes acting as a peacemaker and other times escalating the tension by playing favorites.

Uncle Rondo is Mama's brother and a veteran of World War I. Every Fourth of July, he drinks an entire bottle of an unnamed prescription that leaves him dizzy and erratic. He functions as a volatile presence in the household, easily influenced by the opinions of others. He sleeps on an army cot and has a highly unpredictable temper that quickly leads to property damage when he feels insulted.

Shirley-T. is a two-year-old blonde girl whom Stella-Rondo brings home to Mississippi. Stella-Rondo insists the child is legally adopted, though her sudden appearance causes intense speculation and tension within the household. She tap-dances and speaks with a loud Yankee accent that startles the family.

Mr. Whitaker is a photographer from Illinois who visited China Grove and took portraits of the townspeople. He serves as the catalyst for the deep rift between the two sisters. He dated Sister first before abruptly marrying Stella-Rondo and taking her up north, leaving hard feelings behind in Mississippi.