No records remain of any formal education that Margery may have received, and as an adult, a priest read to her "works of religious devotion" in English which suggests that she might have been unable to read them herself, although she seems to have learned various texts by heart. Margery appears to have been taught the Paternoster (the Lord’s Prayer), Ave Maria, the Ten Commandments, and other “virtues, vices, and articles of faith”. At around twenty years of age, Margery married John Kempe, who became a town official in 1394. Margery and John had at least fourteen children, some of whom likely died during infancy. However, there are records of their eldest son, John, surviving to adulthood.
Kempe was an orthodox Catholic and, like other medieval mystics, she believed that she was summoned to a “greater intimacy with Christ,” in her case as a result of multiple visions and experiences she had as an adult. After the birth of her first child, Margery went through a period of crisis for nearly eight months. During her illness, Margery claims that she envisioned numerous devils and demons attacking her and commanding her to “forsake her faith, her family, and her friends” and that they even encouraged her to commit suicide. Then, she also claims that she had a vision of Jesus Christ in the form of a man who asked her "Daughter, why have you forsaken me, and I never forsook you?". Margery affirms that she had visitations and conversations with Jesus, Mary, God, and other religious figures and that she had visions of being an active participant during the birth and crucifixion of Christ. These visions and hallucinations physically affected her bodily senses, causing her to hear sounds and smell unknown, strange odors. She also reports hearing a heavenly melody that made her weep and want to live a chaste life. According to Beal, "Margery found other ways to express the intensity of her devotion to God. She prayed for a chaste marriage, went to confession two or three times a day, prayed early and often each day in church, wore a hair shirt, and willingly suffered whatever negative responses her community expressed in response to her extreme forms of devotion". Margery was also known throughout her community for her constant weeping as she begged Christ for mercy and forgiveness.
In Kempe's vision, Christ reassured her that he had forgiven her sins. "He gave her several commands: to call him her love, to stop wearing the hair shirt, to give up eating meat, to take the Eucharist every Sunday, to pray the rosary only until six o'clock, to be still and speak to him in thought…”; He also promised her that He would “give her victory over her enemies, give her the ability to answer all clerks, and that [He] will be with her and never forsake her, and to help her and never be parted from her". Margery did not join a religious order, but carried out "her life of devotion, prayer, and tears in public". Indeed, Margery's visions provoked her public displays of loud wailing, sobbing, and writhing which frightened and annoyed both clergy and laypeople. At one point in her life, she is even imprisoned by the clergy and town officials and threatened with the possibility of rape; however, Margery does not record being sexually assaulted. Finally, during the 1420s Margery dictated her Book, known today as The Book of Margery Kempe which illustrates her visions, mystical and religious experiences, as well as her "temptations to lechery, her travels, and her trial for heresy". Margery’s book is commonly considered to be the first autobiography written in the English language.