Lee’s research focuses on East Asian international relations, security, and diplomatic history. Her book, "China's Hegemony: Four Hundred Years of East Asian Domination" (Columbia University Press, 2016) examines how Chinese hegemony in early modern East Asia was not just a product of Chinese power but was shaped by its neighbors' domestic legitimation strategies.
Her second project investigates how China’s rise impacts the American-led international order, specifically through the lens of the U.S. alliance system in East Asia and China. At SIS, she teaches courses on Asian international politics, Korean politics and foreign policy, and North Korea and international security. Prior to AU, she was an Andrew W. Mellon Postdoctoral Fellow in Politics and East Asian Studies at Oberlin College, where she also taught as a visiting assistant professor. She was a POSCO visiting fellow at the East-West Center and a non-resident James Kelly Korean Studies Fellow with the Pacific Forum Center for Strategic and International Studies. She was a Korea Foundation-Mansfield Foundation scholar of the U.S.-Korea Scholar-Policymaker Nexus program.
At AU, she holds the C. W. Lim and Korea Foundation Professorship of Korean Studies.