Sung-jun Bae is a Visiting Fellow with the Korea Program and 38 North at the Stimson Center. He focuses on conducting policy research and promoting international cooperation. His areas of expertise include defense policy, defense industry, logistic support, and economic policy.

During his tenure at the Korea Ministry of National Defense, Bae played a role in promoting cooperation within the Korea-U.S. alliance and with other friendly nations. His responsibilities encompassed conducting defense diplomacy and facilitating defense-military cooperation.

Previously, Bae was responsible for negotiating various Free Trade Agreements at the Korea Ministry of Foreign Affairs. He also worked as a research professor and adjunct professor at universities in Korea.