Trentham teaches courses related to Christian formation and discipleship, and emphasizes the centrality of biblical community and Christian practices in all of his classes. His pastoral experience includes leading local church ministries focused on young adults, missions, and worship. He is the author and contributor to numerous books, journal articles, and research studies, particularly in the areas of Christian higher education and ministry leadership. In 2017, Trentham was elected as President of the Society of Professors in Christian Education (SPCE), the primary scholarly guild for evangelical academicians in the educational and discipleship disciplines. He and his wife Brittany, both originally from East Tennessee, are the blessed parents of two vibrant children. The Trenthams are members of Christ Fellowship Church in Louisville, where John David serves as an elder and worship leader.