LEE Sang Hyun is currently Fellow Emeritus of the Sejong Institute, board member of the Institute of Nuclear Materials Management-Korea (INMM-K), board member of the Asia-Pacific Leadership Network (APLN) for Nuclear Nonproliferation and Disarmament, and Program Director of Seoul Forum for International Affairs. He served as President of the Sejong Institute (2021~2024), researcher at the Korea Institute for Defense Analyses, Director-General for Policy Planning at the Ministry of Foreign Affairs and Trade, a guest researcher at the Stockholm Institute for Security and Development Policy (ISDP) in Sweden, and a visiting researcher at the Stimson Center in Washington, D.C. His main research interests include international politics and security, Korea-U.S. relations, inter-Korean relations, nuclear security and nonproliferation, and East Asian security issues.