O'Connor was a devout Catholic. From 1956 through 1964, she wrote more than one hundred book reviews for two Catholic diocesan newspapers in Georgia: The Bulletin and The Southern Cross.[37] According to fellow reviewer Joey Zuber, the wide range of books she chose to review demonstrated that she was profoundly intellectual.[38] Her reviews consistently confronted Catholicism-defined theological and ethical themes in books written by the most serious and demanding Catholic theologians of her time.[39] Professor of English Carter Martin, an authority on O'Connor's writings, notes simply that her "book reviews are at one with her religious life".[39]
A prayer journal O'Connor had kept during her time at the University of Iowa was published in 2013.[40] It included prayers and ruminations on faith, writing, and O'Connor's relationship with God.[41][40][42]
