His research in political theory focuses on American political thought and critical race theory. His book Between Homeland and Motherland: Africa, U.S. Foreign Policy and Black Leadership in America (Cornell University Press, 2011) won the W.E.B. Du Bois Distinguished Book Award from the National Conference of Black Political Scientists. His papers have appeared in American Political Science Review, Studies in American Political Development, Political Research Quarterly, and Journal of Black Studies, and several other journals.

Professor Tillery is the Founding Director of the Center for the Study of Diversity and Democracy.