Joanna Harrigan married Bert Thomas at sixteen, her parents consenting: her mother feared a lack of suitors, her father trusted Bert's perceived cleverness despite his laziness. An elegant dancer who admired Bert's skill, Joanna envisioned a dancing life. This evaporated upon Bert's alcoholism, volatile temper, and unreliability, compounded by her own difficult pregnancy ending her dancing.

As wife to Bert and mother to Eliza, Horace, Edward, Harry, and Noah, she also became caretaker to her orphaned niece, Anne Shirley. Near-poverty deepened with Bert's employment failures due to drink. Joanna managed survival and childcare, often distressed or angry. Bert frequently hit her, even pregnant, fostering dysfunction. Strained, Joanna directed frustration onto Anne, treating her harshly as a chore girl from age six, disparaging her red hair and showing little kindness.

Eldest daughter Eliza became the family's emotional anchor and primary earner through sewing, often parenting Anne and her siblings. Eliza's elopement with Roger Emerson fractured the household further. Bert's death in a train accident worsened their financial peril, leaving Joanna his debts. This forced her to relinquish Anne for adoption by the Hammonds.

Years after Anne left, Joanna sent her a hat and a letter before Anne's journey to Prince Edward Island. She wrote of improved circumstances and happiness since Bert's death, stating she had "learned how to laugh," wishing Anne well, indicating a shift from her embittered past.

Joanna possessed chestnut brown hair typically secured in a prim bun, reflecting her strained responsibility. Her Hebrew name, meaning "God is gracious," contrasted with her life's harshness.