Manuel joined the faculty of the Georgetown Public Policy Institute in 2009. He is the Founding Director of the Institute for Leadership Studies and Professor of Political Science at Mount Saint Mary's University in Maryland. Manuel is also a Research Fellow at the Berkley Center for Religion, Peace and World Affairs at Georgetown University. He is the author of five books and numerous scholarly articles.

Previously, Dr. Manuel was Department Chair and Professor of Politics at Saint Anselm College. He co-founded the New Hampshire Institute of Politics at Saint Anselm College and served as its Executive Director. He has also taught at the University of Maryland (College Park), Boston University, the University of New Hampshire and in the Government Department at Georgetown. He has received Fulbright and National Endowment for the Humanities grants.

Dr. Manuel is a tertiary of the Dominican Order. He has served on the Executive Council of the New England Political Science Association, and was a Visiting Scholar at the Minda de Gunzburg Center for European Studies at Harvard University.