This dissertation asks why certain commercial organizations but not others become governors of territory and populations. In particular, it investigates what distinct advantages the East India Company possessed in becoming the governor of the Indian subcontinent. Existing explanations assume European superiority in military and fiscal practices, and therefore tend to situate answers to this question within the framework of global divergence in economic and political fortunes between East and West. In contrast, I show that European mercantile companies faced rivals in Asia that were similar to themselves in that they contained a portfolio of powers, including commercial, political, legal, and military prerogatives, and they were engaged in modernization and innovation in military-fiscal methods. Nevertheless, within the context of interstate warfare and stiff competition for resources, only some of these multifaceted commercial groups became governors and established their authority over populations, while others did not. Why was this the case? I argue that the success of groups attempting to become commercial governors depends on the social repertoires, including norms, codes of conduct, and internal relationships that characterize these groups. These social repertoires make groups more or less open to resource holders outside of the organization. Differential access to resource holders produces varying success for commercial organizations in the transition to rule. Through the development of a theory of governing by commercial actors and the case analysis, this dissertation makes two main contributions. The first contribution is to illuminate the distinct process of state building specific to commercial actors and to think critically about how this process may or may not differ from the conventional wisdom regarding state building by dynastic monarchies or, alternatively, other non-state actors. Given the structure of the modern international system and the clear legal distinction between public and private, companies are rarely, if ever, considered legitimate sources of political authority. But work on corporations and politics in topic areas like post-conflict peace building, provision of public goods, and governance in areas of limited statehood have identified commercial groups as key actors. While referencing historic actors like the East India companies in mythological terms, these literatures rarely draw substantive connections between historic state building and modern governance by commercial actors. By focusing on domestic political collaboration between commercial organizations and their constituents, I show what those general dynamics might be and how they can be used to explain governing by commercial actors across space and time. The second goal of the analysis is to provide at least a partial investigation of state building in early modern South Asia. Emerging work on state formation in South Asia has recognized that the conditions of interstate warfare there in the eighteenth century produced early forms of military-fiscalism. However, I show that this military fiscalism did not resemble what emerged in Europe or China because of the pervasive presence and political activity of commercial organizations. This dissertation concludes by considering what the possibilities of commercial governance are in the modern world and what the experience of South Asia in the eighteenth century can teach us about moments of rapid economic transformation and political innovation.