Professor Sheen is an associate professor at the Graduate School of International Studies, Seoul National University. Previously, he was a visiting professor at the East-West Center DC; a CNAPS fellow at the Brookings Institution; an assistant research professor at the Asia-Pacific Center for Security Studies (APCSS); and a research fellow at the Institute for Foreign Policy Analysis (IFPA). His research interests include international security, US foreign policy, Northeast Asian politics, and the Korean Peninsula. He received his B.A. from Seoul National University, and his M.A. and Ph.D. from the Fletcher School of Law and Diplomacy at Tufts University.