She has a daughter named Selena St. George with her abusive husband, Joe. In the novel she also had two sons, named Joe Jr. and Pete, the latter died twelve years after Joe whereas Joe Jr is a democrat politician.
Dolores worked as a maid doing odd jobs around Little Tall Island. She married Joe St. George, who later becomes an alcoholic and would, on occasion, violently abuse her.
She was hired by wealthy widow Vera Donovan, who treated her very coldly (sometimes outright cruelly), often adding to the stress of Dolores's progressively more troubled home life.
After one particular situation where Joe assaults Dolores, she waited until the children are in their rooms and attacked him in return, threatening him to never do it again. This backfired, however, as Selena heard their exchange and came to believe that it was Dolores herself who instigated the fight, which, unfortunately, caused Selena to push Dolores away, and get closer to Joe for a time.
In an effort to smooth out issues in their relationship, Dolores accompanied Selena on a ferry ride home from school. On the ride, Selena reluctantly revealed that Joe had been molesting her. Shocked, Dolores had no idea how to handle things, and her first instinct was to withdraw their children's savings and make a run for it. However, after a meeting with her bank manager, she found out that Joe had already taken all that money for himself.
A short time later, Dolores broke down in tears in front of Vera. Once Dolores was done crying, Vera asked what was wrong and Dolores confided in her how Joe had abused her, molested Selena, and stolen her children's savings. Vera had a veiled discussion with her, indirectly suggesting that she should kill Joe, under the guise of "husbands have accidents".
On the day of a solar eclipse, Dolores got Joe drunk and then tricked him into falling down a boarded-up well in their backyard, with the intent of making it look like he had gotten drunk and fallen down the well by accident. Her plan succeeded, although some members of the community voiced their belief that Dolores had more to do with Joe's death than she claimed.
Afterwards, Dolores and Vera eventually became lifelong friends with a love-hate relationship. At the end of her lifetime, the senile Vera would frequently become agitated, believing herself to be under attack by imaginary entities. On one such occasion, she panicked and ended up wheeling herself down the staircase in her home. Dolores saw Vera run towards the staircase and unsuccessfully tried to stop her. Vera, fearing that she would end up surviving and not wanting to, begged Dolores to kill her. Dolores initially intended to oblige by beating her to death with a stone rolling pin, but Vera died as she went fetching the rolling pin. Standing there with the rolling pin in her hand, she was spotted by the mailman, who made sure Dolores called the police, believing that Dolores had caused Vera's injuries.
Dolores was extensively interrogated by the police. In the novel, which is told in the format of Dolores' recounting of her life's events to the police, Dolores revealed the full truth of her involvement in Joe's death, and continued to assert her innocence in Vera's death. In the movie this truth was not revealed to the police - instead Selena pointed out that the police were trying to use Vera's death as a means of punishing Dolores because they suspected she was responsible for Joe's death. In the end, the police accepted that she had not killed Vera and let her go. It is revealed that Vera had left a large sum of money to Dolores, who was appalled by the thought of accepting it. Instead, she gave it all away in an anonymous donation.
By the end of the story, Dolores and Selena have begun to make amends and Selena accepts her mother back into her life.
Kathy Bates has said that playing Dolores Claiborne is her favorite film role, although she played Annie Wilkes in another Stephen King movie, Misery, and won several awards including an Oscar for her work.