Father Clark is a member of the New England Province of the Society of Jesus, and has been a member of the Holy Cross faculty since 2001. He entered the Jesuits in 1982 and was ordained a priest in 1993, after studies that included an M.A. in philosophy from Loyola Chicago. Following ordination, after serving for several years as a parish priest in Kingston, Jamaica, he returned to the Weston Jesuit School of Theology (now part of the Boston College School of Theology and Ministry) to complete doctoral studies in systematic theology. He specialized in the role of local communities in Catholic ecclesiology, and completed the degree in 2001 with a dissertation that was later revised and published as A Voice of Their Own: The Authority of the Local Parish (Collegeville, MN: Liturgical, 2005). Since joining Holy Cross, he has continued to focus his scholarly work on the theology of parish, and has authored various conference papers and articles related to that theme.