Uninsured and undocumented immigrants risk deportation as well as other social and financial consequences when accessing healthcare in the US. Facing these risks head-on, they do the work necessary to ensure their friends, families, and communities receive medical care. Research at the intersection of linguistic and medical anthropology understands that work to be “communicative care.” Communicative care includes any way that we use language to maintain ourselves. This dissertation utilizes a communicative care framework to demonstrate that immigrant patients are not passive recipients of whatever policymakers determine they deserve; instead, they are structurally competent experts who do communicative care at the institutional and community levels to make a more equitable, accessible, and affordable healthcare system for themselves, their communities, and all patients. The dissertation relies on ethnographic data collected during five years of Philadelphia-based research and fieldwork completed during two overlapping inflection points in the history of US healthcare and immigration – the Trump administration and the COVID-19 pandemic. Ethnographic data includes field notes from longitudinal participant observation, transcriptions of interviews and conversations with undocumented and uninsured Latinx immigrant patients and healthcare professionals, and a corpus of audio-visual materials and policy artifacts. Analysis of this qualitative data revealed that undocumented and uninsured immigrants complete various essential roles within the healthcare system beyond that of the patient. They learn through personal experience what the structural barriers to healthcare are as they navigate through Philadelphia’s patchwork of access points and build lived expertise of sociopolitically constructed inequities. Ultimately, they use this knowledge at the institutional and community level to facilitate access to healthcare in their community. Within the institutional level, they serve as educators and trainers of medical professionals who want to understand the policy-based limitations placed on different patient populations and the clinical strategies needed to improve patient services. At the community level, they serve as advocates who organize and participate in large-scale systems change and representatives for the full ratification of immigrant access to healthcare. This project contributes to anthropological research on two of the most defining sociopolitical issues of the 21st century - immigration and healthcare. Often portrayed as victims and undeserving of our charity, we have yet to fully consider the lived expertise of uninsured and undocumented immigrant patients as we draft responses and solutions to urgent and emerging problems like the simultaneous drop in US life expectancy and rise in healthcare spending. This dissertation recasts immigrant patients as experts who actively engage in healthcare reform through everyday responses to the structural barriers that subvert their access to healthcare and undercut healthcare professionals’ capacity to provide medicine. By illuminating the roles of undocumented and uninsured immigrant patients and the manifestation of their lived expertise across multiple levels of analytic granularity, this project offers new possibilities for future healthcare policies, politics, and practices in and beyond the US. / Anthropology