Daniel Koss studies political parties in East Asian politics. His first book, published in 2018, investigates the role of political parties under authoritarianism through the case of the Chinese Communist Party. Asking why the Chinese state is "stronger" in some areas of its realm than in others, his research demonstrates the importance of the party's rank and file for effective local governance. His second book manuscript studies East Asia's other super-resilient ruling party, namely the Liberal Democratic Party of Japan.

Approaching contemporary outcomes from a long historical perspective, his field of research covers the Cultural Revolution (1966-1976), the Great Leap Forward (1958-1961), the Second Sino-Japanese War (1937-1945), and even the governance reforms of the Yongzheng Emperor (r. 1722-1735). Koss's research on Japanese parties adopts a similarly long-term perspective, with one of his ongoing projects studying the emergence of political parties in the early Meiji era.

Koss has spent years doing research in mainland China (Beijing, Hubei, Shandong, Zhejiang), Taiwan and Japan (Miyagi, Nagano, Shiga, Tokyo, Toyama). He holds a PhD in political science from Harvard University, worked as an Assistant Research Fellow at the Institute of Political Science at Academia Sinica (Taipei), and since January 2019 serves as a lecturer at the Department of East Asian Languages and Civilizations.