His research is focused on nuclear receptor signaling and epigenetic gene regulation in prostate cancer. Campbell served as associate professor of Oncology and associate member of the Department of Pharmacology and Therapeutics at Roswell Park Cancer Institute, a position he held beginning in 2007. From 2011—2015, he served as associate dean of the Roswell Park Graduate Division at the University at Buffalo, State University of New York; in 2015, he became a distinguished member of the graduate faculty.