This dissertation builds on the current anthropological studies of care relations in practice. It draws inspiration from science and technology studies (STS) and postfeminist technoscience. A qualitative ethnographic approach grounds the empirical data collection and analysis. This entails ethnographic fieldwork with senior home care in the United States and Sweden during 2007–2008 and 2011–2012. Analytical attention centers on how movements situate various tensions of senior home care in practice. Four interrelated published works comprise the main thematic chapters. Each article exemplifies how human and nonhuman relations move and mediate care. They develop several heuristic terms that advance ideas about how older people, aging bodies, technologies, spaces, and times that tinker each other through movements of care in practice. The comprehensive summary frames these articles with an overview of the primary thematic orientations and methodological concerns. A discussion of the main contributions and implications of the dissertation concludes the work.