Justin is an Episcopal priest (serving as the canon for vocations in the Diocese of Central Florida), teaches theology, philosophy, and Christian thought at Gordon-Conwell-Theological Seminary and Reformed Theological Seminary, and serves as a director at Key Life. He previously taught at the University of Virginia and Emory University. Justin holds two masters degrees from Reformed Theological Seminary and a Ph.D. from Emory University.

Justin wrote On the Grace of God, and Acts: Knowing the Bible. He and his wife, Lindsey, are authors of Is It My Fault?: Hope and Healing for Those Suffering Domestic Violence and  Rid of My Disgrace: Hope and Healing for Victims of Sexual Assault. He is also the editor of Christian Theologies of Scripture: A Comparative Introduction (NYU Press, 2006), Christian Theologies of Salvation (NYU Press, forthcoming), Christian Theologies of Sacraments (NYU Press, forthcoming).

Since 2001, Justin has traveled to southern Sudan to train chaplains in the Sudanese People’s Liberation Army. He and Lindsey founded Mosaic, a nonprofit that initiates projects to alleviate suffering in southern Sudan and Uganda.

Justin serves on the boards of REST (Real Escape from the Sex Trade) and GRACE (Godly Response to Abuse in Christian Environments). He also serves on the council board of the Biblical Counseling Coalition.