Barkley received his PhD from the University of Texas-Austin in 1974. He was trained as a medievalist and is particually interested in the Church Fathers. In addition to teaching at colleges in Texas, Ohio, Michigan, and Germany, he has worked as a professional editor and writer for 25 years. He is an ordained Deacon and served in the Diocese of Austin. He is a parish director of religious education, a former president of the Texas Catholic Historical Society, and a member of teh Mariological Society of America.