This thesis, ‘Advocates of the Poor’, presents an ethnographic study of the practices of Irish general practitioners (GPs) who deliver primary care to marginalised populations, including individuals who experience rural isolation and loneliness, homelessness, addiction, asylum-seeking, systemic exclusion and inability to access secondary healthcare services. Framed within the discipline of human geography, the study interrogates the spatial, relational, and ethical dimensions of care provision in contexts marked by precarity and institutional constraint. Drawing on immersive fieldwork, semi-structured interviews, and participant observation, the research foregrounds the lived experiences of GPs whose work frequently transcends conventional clinical boundaries. Research participants engage in forms of care that are mobile, improvised, and deeply relational, often operating in informal and under-resourced settings. The study critically examines how such practices reconfigure the geographies of healthcare and challenge dominant models of biomedical governance. It also shows how GPs themselves draw strength from ‘making a difference’. The thesis contributes to debates in health geography and critical medical anthropology by conceptualising general practice as a spatial and political act. It argues that the provision of care to marginalised groups constitutes a form of placemaking and resistance, wherein GPs navigate and reshape the sociomaterial landscapes of Irish health policy, austerity, and migration. The analysis reveals how GPs mobilise ethical commitments and professional autonomy to mitigate structural violence and advocate for more inclusive forms of healthcare. By situating general practice within broader socio-political and spatial contexts, including the COVID-19 pandemic, this research suggests a nuanced understanding of primary healthcare as a situated, contested, and transformative practice. It offers original insights into the everyday geographies of solidarity enacted by GPs working at the margins of the Irish healthcare system and calls for a reimagining of primary care as a site of both medical intervention and social justice.