Maria is a 26-year-old woman from a prosperous family who is unjustly imprisoned in a grim asylum by her husband. She is highly educated, sensitive, and deeply devoted to her child. Having grown up in an emotionally neglectful home where her older brother was favored, she is prone to romantic idealism and seeks comfort in reading and writing to pass the time in confinement.

Jemima is a working-class woman employed as an attendant at the asylum. Born illegitimate and orphaned days after birth, she has endured severe trauma, poverty, and exploitation. These harsh experiences have made her pragmatic, self-protective, and highly suspicious of others, though she possesses a sharp intellect and a latent capacity for empathy that awakens as she observes Maria.

Henry Darnford is an aristocratic young Englishman who finds himself unjustly imprisoned in the same asylum as Maria. He is well-read and sensitive, leaving marginalia in books that immediately capture Maria's interest. Having spent time in America after serving in the British army, he possesses a restless, somewhat flighty, and inconsistent nature.

George Venables is Maria's estranged husband, a superficially handsome but deeply selfish man who views his wife purely as an asset. Coming from a merchant family, he frequently drinks to excess, gambles, and spends beyond his means. He aggressively uses his legal authority to control Maria, punish her independence, and access her finances.

Maria's unmarried uncle is a wealthy and kindhearted man who suffered a romantic disappointment in his youth. He takes a special interest in Maria, encouraging her education and trying to secure her future financial independence. He fundamentally disagrees with the societal rules that trap women in abusive marriages.

Mr. S is a well-educated, charming friend of George Venables. He spends a significant amount of time at the couple's home, engaging in flirtatious behavior with Maria while secretly involving himself in George's financial troubles.

Peggy is the sister of Maria's old nurse who falls into precarious circumstances following the death of her husband. Her situation serves as a catalyst during Maria's early courtship with George.

Maria's eldest brother grows up as a spoiled, cruel young man due to his parents' extreme favoritism. He feels entitled to the family's resources and aggressively resents any financial independence granted to Maria by their uncle.

Maria's father is a strict and demanding parent who largely neglects his younger children in favor of his eldest son. Following his first wife's death, he begins an affair with a lower-class woman, which further fractures the household and pushes Maria toward an early marriage.

Maria's mother is a distant parent who heavily favors her eldest son over her other children. She relies entirely on Maria for care during her final illness, despite her lifelong emotional neglect of her daughter.

Maria's infant daughter is the absolute center of her mother's world. Taken from Maria shortly after birth as part of a cruel plot, the baby represents Maria's only source of hope and her sole motivation to secure her freedom.

A servant who refuses to marry Jemima's mother after getting her pregnant. He actively neglects his illegitimate daughter after her mother's death and eventually sends her away to be mistreated by others, ensuring her childhood is filled with hardship.

A working-class servant who becomes pregnant out of wedlock. Terrified and denied any help or marriage by the child's father, she dies just days after giving birth, leaving her daughter completely vulnerable to an uncaring world.

The master of the household where Jemima works as a teenager. He aggressively abuses his position of power by assaulting and blackmailing her, demonstrating the extreme vulnerability of working-class women without family protection.

A woman running a shop whom Maria previously assisted financially. She is trapped in her own unhappy marriage to an alcoholic husband, which severely limits her ability to fully shelter and protect Maria from pursuit.