This dissertation studies the relationship between military mobilization and empire-building in China during the Mongol-Yuan (1260/1271-1368) and the Ming (1368-1644) dynasties. Utilizing a variety of central-level and local sources, it traces the rise and fall of hereditary military service between the mid-thirteenth and early seventeenth centuries. Although hereditary military service played an important role in both empires, the Yuan and Ming also ultimately moved away from it in favor of other methods of mobilization. While previous scholarship has often viewed this transition in terms of decline and collapse, this dissertation instead argue that we should see changes and adjustments to the military as signs of the state’s flexibility and resolve in adapting to new socioeconomic conditions, changing patterns of warfare, and new institutional realities. By exploring changing military policies and institutions, this study considers how the late imperial Chinese state mobilized resources and utilized different policy measures to achieve its military goals and the long-term impact that military institutions had on war-making, fiscal institutions, and the organizational capacities of the bureaucracy. Additionally, by engaging with scholarship with other parts of Eurasia, this dissertation places China within a broader Eurasian context of warmaking and empire-building. It does so by comparing the Mongol-Yuan with its sedentary cousin the Ilkhanate in Persia and the Ming with another post-Mongol empire, Muscovy Russia. In doing so, it sheds light on how the Mongols adapted their military to function in sedentary conditions and to respond to new geopolitical threats while also revealing how post-Mongol polities grappled with their Mongol institutional heritage, utilizing both similar and different methods.