Dolores is a 65-year-old widow who has spent over four decades working as a maid and eventual live-in companion for the wealthy Vera Donovan on Little Tall Island. Hardened by years of difficult manual labor and severe domestic abuse, she possesses a gruff exterior and a fiercely protective nature toward her children. Driven to the brink by her husband's escalating cruelty and theft of her savings, she resolves to take extreme measures to save her family from further harm.

Vera is a wealthy, cantankerous woman originally from Baltimore who moves permanently to Little Tall Island. Known for her demanding nature and strict household rules, she routinely plays psychological games with her staff to assert her dominance. Despite her harsh demeanor and descent into senility, which includes terrifying hallucinations of "dust bunnies," she develops a complex, co-dependent bond with Dolores over their decades together.

Joe is a resident of Little Tall Island who marries Dolores when she becomes pregnant as a teenager. He is a cruel, manipulative man who spends the family's hard-earned money on alcohol and gambling while using his stints in recovery to garner local sympathy. His escalating physical and emotional violence toward his family, combined with his disturbing fixation on his teenage daughter, forces Dolores to take desperate actions.

Selena is the eldest child of Dolores and Joe St. George. Initially a bright and talkative teenager who does well in school, she undergoes a drastic personality change as her home life deteriorates. She becomes increasingly withdrawn, donning baggy clothing and avoiding her family as she bears the secret brunt of her father's inappropriate advances and abuse.

Joe Junior is the middle child and older son of Dolores and Joe St. George. Unlike his father, he is an excellent student who prefers reading books to traditional masculine pursuits. He frequently endures harsh criticism and belittlement from his father, which fosters a deep-seated hatred for the man and a desire to distance himself from the household.

Little Pete is the youngest child of Dolores and Joe St. George. Impressionable and eager for his father's approval, he begins to idolize Joe, adopting his violent and discriminatory language. This mimicry deeply worries Dolores, who fears her youngest son will grow up to perpetuate the cycle of abuse.

Jessie is a young girl whom Dolores senses and envisions during the darkness of a total solar eclipse. Though separated by distance, the two share a profound, mysterious psychic connection forged through their parallel experiences of hidden trauma. This brief moment of solidarity leaves a lasting impression on Dolores.

Dr. McAuliffe is the county medical examiner who investigates the circumstances surrounding Joe St. George's fate. He is highly suspicious of Dolores's account of events, noting discrepancies in her story. During official questioning, he aggressively pushes her in an attempt to uncover the truth behind the incident.

Andy is a local police officer who listens to Dolores Claiborne's lengthy confession. Because he grew up in the closed community of Little Tall Island, Dolores remembers him picking his nose at church when he was a boy. His presence during the interrogation proves that everyone in the small town knows each other's history intimately.

Mr. Donovan is Vera's deceased husband, whose memory continues to cast a long shadow over her life. Vera frequently experiences terrifying hallucinations of dust bunnies that she attributes to his lingering, threatening presence.