Dr. Douglas “Jake” Jacobsen began working at Messiah in 1984, where he taught courses on church history, theology, regional Christianity, and World Christianity and conducted research on topics ranging from to global Pentecostalism to political and cultural divisions within America's churches. In 2003, his book Thinking in the Spirit: Theologies of the Early Pentecostal Movement (Indiana University Press) received the Pneuma Award from the Society for Pentecostal Studies. The second edition of his university textbook The World’s Christians: Who They Are, Where They Are, and How They Got There (Wiley/Blackwell) was released in 2021. Global Gospel (Baker), which describes worldwide Christianity for a broader readership, was published in 2015. His most recent publication is What Is Christianity? (Wiley/Blackwell, 2022).

From 2015–2020, Jake was the co-director (with Rhonda Hustedt Jacobsen) of the Clergy Leadership Program of Central Pennsylvania, a project funded by the Lilly Endowment designed to identify emerging pastoral leaders and connect them to other community leaders. Jake and Rhonda continue to co-direct the Religion in the Academy Project which studies connections between religion and higher education. Their joint publications include Scholarship and Christian Faith: Enlarging the Conversation (Oxford University Press, 2004), The American University in a Postsecular Age (OUP, 2008), winner of the Lilly Fellows Book Award, and No Longer Invisible: Religion in University Education (OUP, 2012), winner of a Critics Choice Award from the American Educational Studies Association.