The health care system in the United States is sick. Despite leading the world in health care expenditures, the U.S. lags behind most industrialized nations on many dimensions of health care outcomes. With the growing cost of and increasing demand for health care services, entrepreneurs are needed to develop and implement innovative solutions. However, entrepreneurship is a complex process, particularly in highly institutionalized fields such as health care where entrepreneurs must navigate a complex array of social obstacles. In this dissertation, I investigate entrepreneurship in the field of health care through the lens of institutional theory. I pay special attention to the role of culture embedded in the local region as well as the professional field and investigate how these social forces shape entrepreneurial activity. In this way, this dissertation returns to the foundational (yet rarely studied) premise of institutions as the building blocks needed to create new organizations (Meyer & Rowan, 1977). The first chapter presents a systematic review of the literature that links culture to entrepreneurship. Reviewing all articles published in the top management, entrepreneurship, and sociology journals over the past 20 years, I find that extant literature in this area is sparse and has overwhelmingly focused on national cultural differences based on the dimensions of culture developed by Hofstede (1984). The second chapter sets the stage for the empirical analysis conducted in the final chapter. This section traces the emergence of ambulatory surgery centers (ASCs) in the United States and dives into the contextual details surrounding the technical and social factors enabling the emergence of this new kind of health care facility. The final chapter develops and tests theory related to how institutions shape entrepreneurial activity. Here I explore how pressures that constrain entrepreneurship in one social sphere may be overcome by institutional pressures that facilitate entrepreneurship in other social spheres. Using panel data on all physician-founded ambulatory surgery centers in the United States from 1990 to 2008, I find that institutional forces associated with the regional culture, organizational field, and profession influence the propensity for doctors to become entrepreneurs and shape the strategies they adopt.