Dicey Tillerman, the novel's protagonist, becomes a mother to her younger siblings at the age of thirteen when Momma abandons her children in a parking lot. Dicey is accustomed to adult responsibility, however. For as long as Dicey can remember, Momma struggled with the responsibility of raising her children, and Dicey learned early to be strong and resourceful. Dicey loves her mother intensely despite her shortcomings, and, as her peers tease Dicey because their mother is poor and unmarried, Dicey learns early to fight viciously and to avoid contact with others. Dicey begins the novel as a tough loner, unwilling to trust or rely upon others. The only people with whom Dicey opens up are her family members, whom she loves dearly and defends ferociously. Even with her siblings, however, she finds herself fabricating lies to protect them from truths she thinks are too much to bear. In fact, Dicey is so determined and proud, that she hides her own emotions from herself. When Momma leaves, Dicey refuses to linger on the implications of their abandonment and instead focuses intently on the goal of traveling with her brothers and sister to Bridgeport. She accepts the truth of Momma's mental health and breakdown because she must, but she does not linger on it, examine it, or react to it, except for one night of tears with her siblings. Even while pragmatically and brusquely facing the truth, Dicey stubbornly clings to her devotion to her mother. Throughout the novel, Dicey is driven by her determination to survive, to keep her family together, and to find them a place where they can "stay and be." She grows in her understanding of her family's importance and identity and of life's transience and impermanence, but she deals only superficially with her emotions about her mother. These emotions form the thematic material of the book's sequel, Dicey's Song.
Dicey's twelve-year-old brother is a cerebral and curious young man. Unlike Dicey, he is not strong and tough, and he responded to the cruelty of his peers by becoming even more deeply involved in his studies. James finds himself in more liminal position than Dicey: he is neither the adult of the group nor is he a child. At times he rebels against Dicey childishly, like Sammy. Other times, he passively allows Dicey to make decisions and provide for them, whereas he also assesses their situations and plans their next moves more quickly and cleverly than Dicey. James bombards Dicey with his philosophical musings on mortality and morality, he listens thirstily when Stewart lectures him carefully about stealing, and he thrives at the Catholic school in Bridgeport, where the priests love learning almost as much as James. Like Dicey, James has a difficult time reconciling himself to Momma's actions, and unlike Dicey, who represses bad memories and clings stubbornly to her convictions about Momma, James speaks harshly and realistically about what Momma has done, often arousing Sammy's ire.
Eight-year-old Maybeth is a quiet girl almost crippled by shyness. In Provincetown, her shyness interfered so severely with her studies that she was held back in school, and the label of being retarded always lingered around her ominously. Dicey and her family know that Maybeth is not retarded, because she displays skill in learning lyrics and music, singing, and perceiving and assessing people's real characters and motivations. Throughout their trip, Dicey struggles between protecting Maybeth and addressing her with the truth of their situation. Dicey, however, is always surprised that when she tells Maybeth a painful truth, because Maybeth understands it completely and often already knew it. At the same time, Dicey never pushes Maybeth to do anything that scares her. Maybeth resembles Momma most out of the children: she is pretty, blond, sweet-tempered, quiet, and absentminded. At the end of the novel, Gram forces Dicey to let Maybeth face a challenge on her own. Gram talks frankly to the young girl about what she must do and why, Maybeth meets the challenge successfully.
The youngest Tillerman child at six years old, Sammy is the most passionate and rash. He believes perhaps even more strongly and stubbornly than Dicey in Momma, but lacks the drive that forces Dicey to accept painful truths and move on. Early in the novel, Dicey finds herself reminiscing about a younger Sammy, who was wildly joyful and uninhibited. In Provincetown, however, Sammy learned, like Dicey, to fight in response to the taunts of his peers. Sammy is a fierce fighter and as quick and vehement as Dicey about defending his family members. The six-year-old Sammy is angrier, more stubborn, and more belligerent than the younger child she remembers. Sammy poses a number of problems for Dicey throughout the novel, as he repeatedly refuses to go on walking, he steals food and a wallet, and in Bridgeport, he engages in fights with the other schoolchildren, greatly upsetting Eunice. In Crisfield, Sammy forces the crisis between Dicey and Gram when he disappears all afternoon without permission. At the same time, Sammy's fierce idealism, hope, and his intense moments of joy lift the spirits of the suspicious Tillermans.
Momma's mother, Gram, is as fierce, stubborn, and independent as Dicey and Sammy and as eccentric as Momma. Gram has endured a marriage to a man whom she neither loved nor particularly liked, but she stood by him completely, even though she grew increasingly angry at his actions. Gram's anger warped her relationship with her children, resulting in her driving each of them away from the house and estranging them from her for the rest of their lives. When Gram's husband dies, she is relieved to be free from her promise. She withdraws into herself on her run-down farm, trying to live as far as possible from the world and memories, which cause her pain and guilt. When the children first meet Gram, she is balled up like a fist or a knot of wire. She speaks sharply and harshly to them, she shows no kindness or affection, and she tells Dicey that the children cannot stay with her. At the same time, she finds herself reaching out to them almost despite herself when she convinces Dicey that the children should stay the first night. This opening lets Dicey know that part of Gram does want the children in her life. The children's presence softens Gram, and finally, in her own act of reaching out, she admits that more than anything, she is afraid of repeating her mistakes of the past and hurting and driving away these children as well. Gram's decision to take the children in is as great an act of courage and self-transformation as Dicey's decision to walk with the children to Bridgeport.