Dr. Sean Nicholson-Crotty joined O'Neill in 2013 and specializes in public management and federalism. He currently serves as director of the Ph.D. in Public Affairs and Joint Ph.D. in Public Policy Programs. His primary areas of research also include intergovernmental relations and the diffusion of public policies among subnational governments. He has published more than four dozen articles on these subjects in top public affairs and political science journals. 

Before coming to O'neill, Nicholson-Crotty spent nine years at the University of Missouri where he held a joint appointment in political science and the Truman School of Public Affairs. While there, he earned the Provost's Outstanding Junior Faculty Research and Creative Activity Award, presented annually to the most productive and prominent assistant professor at the university.

Research appointments prior to Missouri included the Public Policy Research Institute, the National Latino Project, and the Texas Educational Project at Texas A&M University where he received his doctorate in political science.