Nannie was born on November 4, 1905, in Blue Mountain, Alabama, which is now part of Anniston. Her parents were Louisa "Lou" (née Holder) and James F. Hazel. Nannie was one of five children, having one brother and three sisters. Both she and her mother disliked James because he was controlling and abusive. He forced his children to work on the family farm and didn't let them go to school, which made Nannie do poorly in her studies.

When Nannie was seven, her family was on a train trip to visit relatives in southern Alabama. During the trip, the train stopped suddenly, and Nannie hit her head on a metal bar. This accident caused her to suffer from severe headaches, blackouts, and depression for many years. Nannie believed that this accident was the reason for her mental problems.

As a child, Nannie loved reading her mother's romance magazines and dreamed of having her own romantic future. She especially liked reading the lonely hearts column. Her father, James, did not allow Nannie and her sisters to wear makeup or nice clothes because he thought it would protect them from men. He also did not let them go to dances or social events.

Nannie Doss, known as "The Giggling Granny," committed several murders over her lifetime. Her killing spree began with her second husband, Robert Franklin Harrelson. In 1945, after he raped her, Nannie put rat poison in his corn whiskey, and he died that same night.

Nannie's third husband, Arlie Lanning, was also a victim. They met through a lonely hearts column and got married. Arlie was an alcoholic and often cheated on Nannie. But it was Nannie who would disappear for months. When Arlie died of what people thought was heart failure, Nannie played the grieving widow. Shortly after, their house burned down, and Nannie collected the insurance money. 

She didn't stop there. Nannie married Richard L. Morton in 1952. He was unfaithful, and before she killed him, she also poisoned her own mother. Richard died in May 1953 from poisoning. 

Nannie’s final victim was her fifth husband, Samuel Doss. They got married in June 1953. Samuel was a minister and didn't approve of Nannie's romance novels. In October 1954, Samuel was hospitalized with flu-like symptoms but was sent home after treatment. A week later, Nannie killed him with arsenic to collect his life insurance. 

The suddenness of Samuel's death raised suspicions, and his doctor ordered an autopsy. The results showed a large amount of arsenic in his body, leading to Nannie's arrest. 

During her trial, Nannie confessed to killing four of her husbands, her mother, her sister, her grandson, and her mother-in-law. The state of Oklahoma only tried her for Samuel Doss’s murder. She pleaded guilty and was sentenced to life in prison in 1955. They did not pursue the death penalty because she was a woman. Nannie Doss spent the rest of her life in prison and died from leukemia in 1965. She was buried in McAlester, Oklahoma.