Mary Johnson joined the Missionaries of Charity, the group commonly known as the Sisters of Mother Teresa of Calcutta, at age 19. Mother Teresa trusted her and she rose quickly in the ranks. Mother Teresa sent Mary to study theology at Regina Mundi, a pontifical institute aggregated to the Gregorian University in Rome, where she received a diploma in religious studies, summa cum laude. For 15 of Mary Johnson's 20 years as a sister, she was stationed in Rome and often lived with Mother Teresa for weeks at a time. After leaving the sisters in 1997, Johnson completed a BA in English, summa cum laude. She subsequently received an MFA in Creative Writing. She also married. A well-respected teacher and public speaker, she has led retreats, workshops, classes, and training sessions of various kinds for nearly thirty years. She currently teaches creative writing and Italian to adults and is Creative Director of A Room of Her Own Foundation's retreats for women writers.