M.J. Thompson was born in Lincoln, England in 1985. As the third child of her mother's and the fourth of her father's, she had a lively upbringing surrounded by four older siblings and four younger ones. This large family included three sisters and one brother both older and younger, ensuring she was never short of company.

Growing up, M.J. went through many phases, including aspirations to be a mechanic, a historian, and a midwife. However, her only constant dream was to become a published author. In school, her favorite subject was always English literature. Her creative storytelling was often praised, and she frequently shared her stories with friends and siblings.

After finishing school, she spent some time traveling around England. Eventually, M.J. Thompson married her long-term partner.