In recent decades there has been an increasing trend toward “constitutionalizing” health—identifying health as a right in national constitutions. Today more than half of written constitutions in the world contain such a right. Whether that is good, bad, or immaterial for the production of population health, however, is much debated. Does constitutionalization improve wellbeing or might it simply distract from or distort good health policy? This dissertation uses a nested analysis that pairs a large-N statistical analysis of 40 years of global health data with in-depth interviews with over 165 policymakers, activists, elected officials, lawyers, and judges in South Africa, India, Malawi, and Thailand. Empirical evidence shows that constitutionalizing health is a significant development in the institutions of health governance and can contribute to improved wellbeing. Over forty years of global health data, we can observe a small but significant health dividend for countries that have adopted the right to health, when controlling for the major alternative explanations of cross-national variation in mortality. Tracing health policy issues in South Africa and India reveals a right that operates as a “policy anchor”—tying health to the fundamental national political bargain and providing an innovation in the institutions of governance that helps policy entrepreneurs gain a foothold from which to drive policy to expand health capabilities. Shadow cases in Thailand and Malawi show that this shift can matter even without judicial intervention but depends on sufficient support structure to enable the full institutionalization of health as a right. These findings contribute to literature on law and rights, sharpen models of the public policy process, and respond to the need to better understanding the broader set of institutions in the political economy of development that drive improvements in population health. In a broader context, this study suggests that constitution-writing is health policymaking. Greater attention to constitutions and the process of institutionalizing rights is warranted for those engaged in global health, with implications for the U.S. and other countries of the global North as well.