Agnes: The chambermaid at the Parkinsons'. She defends Grace against accusations of Grace not telling the truth about Mary.
Dr. Bannerling: The director of the asylum. He thinks Grace is pretending to be ill and believes she did commit murder. He attempts to keep her in the asylum.
Mrs. Burt: Rents a room to Grace's family when they come to Toronto. She befriends Grace's father and introduces Grace to the Parkinsons' as a maid.
Dr. Jerome Dupont: He is a charlatan who is in love with Grace and asks her to leave the Kinnear manor to come travelling with him. He appears in several disguises in the novel.
Govenor's Wife: She employs Grace, but does not trust her.
Mrs. Rachel Humphreys: She begins a personal relationship with Dr. Jordan after her husband leaves her. When Dr. Jordan leaves her, she writes to his mother to find his whereabouts.
Dr. Sime Jordan: He becomes interested in Grace's case a few years after she has been imprisonned, but leaves without having made any conclusions. He later starts a relationship with Rachel Humphreys, but leaves to Europe where life is less stressful for him. He later returns to America and is involved in the Civil War.
Mr. Thomas Kinnear: He is Grace's second employer. He is well-to-do, and had an affair with his housemaid, Nancy Montgumery. He is a known womanizer, and Grace openly flirts with him, which causes his arousal, and Nancy's jealousy. He is later killed with a bullet to the head, presumably by James McDormant.
Miss Lydia: The oldest of the govenor's two daughters. She has a crush on Dr. Jordan and openly flirts with him. Despite his arousal and slightly flattered, he doesn't go after her.
Kenneth McKenzie: He is Grace's lawyer and tells her to pretend to be stupid. According to him, he believes Grace is guilty.
Grace Marks: She is the main character of the novel, and is accused of killing Nancy Montgumery. She then relates her story to Dr. Jordan, and often maintains a somewhat innocent manner. Grace was told by her lawyer to pretend to be mad, even though he believes she is guilty. In the end of the story, it is so imcomplete no one knows if she is lying or not, so she wins her pardon and later marries Jamie, a boy who had a crush on her.
James McDermott: The young stable boy at the Kinnear house. He is often short of temper, and Nancy decided to ask him to leave, which angered him. He is accused of killing Nancy and Thomas, and is then hanged.
Nancy Montgumery: The housemaid at the Kinnear house. She often puts on airs that she is better than Grace, and has a relationship with Thomas Kinnear. When Thomas leave for two days, she warms up to Grace, but later dismisses her again. She is then found dead in the cellar by strangulation and her throat slit.
Mrs. Alderman Parkinson: The mistress of the house where Grace finds her first job.
Mr. George Parkinson: The son of Mrs. Parkinson. He is very weak, and starts a relationship with Mary Whitney, impregnanted her, then left her.
Aunt Pauline: The sister of Graces' mother. She lives in Ireland and often would send money to Grace's family. But when she has her own family, her husband, Roy, tells her to stop so they can support themselves. She later sends enough money so they can move to Toronto for a better future.
Mrs. Quennell: A famous hypnotist who tries to find out the spirit who inhabits Grace at the time of the murder. She believes it is someone else talking through Grace.
Uncle Roy: Grace's uncle who helps pay to support Graces' family until his own wife has a family.
Reverend Verringer: Part of an organization to help free Grace from prison. Later, he is successful.
Jamie Walsh: A young servant boy at the Kinnear household who developes a crush on Grace. Later, he is instrumental to both her conviction and release. Once Grace is freed, he marries her, and to take care of her.
Mary Whitney: A girl whom Grace befriends at the Parkinson household. When Mary becomes pregnant from Mr. George, she gets an abortion but dies from it . Later, its believed that her spirit stayed with Grace.