Joel was the provost of ÃÛÌÒapp from 1996 to 2006 and then was the founding director of the  until retiring in 2019. He has enjoyed being a member of the history department all along. Joel has a longstanding interest in American religious and cultural history and now studies Christianity in Africa and Asia. After writing four articles on Bediako, he has had to give up the larger project. Joel says, "Life is too short, and I have too many other obligations."

Joel was the chair of the board of the Overseas Ministries Study Center (OMSC) when it sold its property in New Haven and merged Princeton Theological Seminary (PTS) in 2020. He still serves on OMSC's advisory committee at PTS. He also chairs the board of Langham Partnership USA, the American affiliate that exists to support and fund the work of Langham Partnership International (LPI). LPI funds doctoral studies and mentors up and coming Majority World theologians, publishes Majority World theology via Langham Publishing, and via Langham Preaching, operates networks of preaching clubs and training programs in 80 countries to equip pastors in biblical exegesis and biblical preaching.

Joel consults for various research and faculty development projects as senior fellow at Nagel. The latest is the $1.9 million, 4-year, global study of spiritual and character formation in seminaries.

Finally, Joel edits a book series for Baylor University Press, Studies in World Christianity.