Thomas Verner Moore , a Catholic priest, psychologist, and psychiatrist, developed a Catholic psychiatry in the first half of the 20th century. Following a brief description of Moore's life, this article develops his psychiatric theory, beginning with its grounding in Thomistic philosophical thought. The relationship between reason and faith, the place of the soul in psychological theory, and a central role for Catholic moral teaching were three Thomistic principles vital to Moore's thinking. Defining psychology as the science of personality, and the study of personality as central to psychiatry, Moore articulated a theory and practice of psychotherapy that he contended was scientifically sound. Although his clinical work did not impose religious teachings on patients, if such teachings were meaningful to them, he did discuss them in sessions; moreover, Catholic moral teaching was a compass in his treatment of patients. The article includes a brief history of the psychiatric clinic that Moore first established in 1916 and its successor.