His formation included undergraduate studies at the University of Detroit, philosophical studies at Bellarmine School of Theology in North Aurora, Illinois, and theological studies at the Jesuit School of Theology at Berkeley, California. Prior to ordination he taught high school English at St. John's Jesuit High School in Toledo, Ohio, and served for one year on the staff of Gesu Parish, Cleveland, Ohio. Other internships include two quarters of clinical pastoral education and three summers in community organizing work. Following ordination in Cleveland, Ohio, on June 19, 1976, he spent a number of months learning Spanish at the Instituto de Idiomas of the Maryknoll Fathers in Cochabamba, Bolivia. From 1977 to 1980, he was associate pastor of St. Patrick Parish, Bridge Ave., Cleveland, Ohio. He served one year in the Office for Hispanic Affairs of the Archdiocese of Detroit when he also worked in hispanic ministry in Port Huron, Michigan.

   Fr. Scullin served Nativity Church in New York City as associate pastor from 1983 until 1986. After that, he served as campus minister at the University of Detroit. From 1989 to1990, he was interim director of a multi-service neighborhood center, St. Malachi Center, in Cleveland. As an associate director of the National Jesuit Office for Social Ministry of the Jesuit Conference, he was a principal organizer of a national conference Faith Doing Justice in Detroit in 1991. From 1991 until 1998 he served as pastor of Holy Rosary/St. John Parish in Columbus, Ohio. He pronounced final vows in the Society of Jesus in 1993.

   Following the completion of the Doctor of Ministry Program at the Catholic Theologican Union in Chicago, he returned to the Detroit Province as Provincial Superior. In the past, Fr. Scullin served as Provincial Assistant for Pastoral Ministry and, from 1993-1999, as province consultor.