Never before have humans wielded a greater ability to alter and disrupt planetary processes. Our impact is becoming so noticeable that a new geological epoch has been proposed – the Anthropocene – in which Earth systems might no longer maintain the stable and predictable conditions of the past 12 millennia. This is particularly evident in the rapid expansion of urban areas, where a majority of humans now live and where environmental changes such as rising temperatures and habitat loss are happening faster than elsewhere.  In light of this, questions have been raised about what a more responsible relationship between humans and the rest of the planet might look like. Scholars in sustainability science employ the concept of ‘stewardship’ in searching for an answer; however, with multiple different applications and definitions, there is a need to better understand what stewardship is or what novelty it might add to sustainability research. This thesis investigates stewardship empirically through two case studies of civic engagement for protecting nature in cities – Bengaluru, India and New York City, USA. Further, the thesis also proposes a conceptual framework for how to understand stewardship as a relation between humans and the rest of nature, based on three dimensions: care, knowledge and agency. This investigation into stewardship in the urban context uses a social–ecological systems approach to guide the use of mixed theory and methods from social and natural sciences. The thesis is organized in five papers. Paper I reviews defining challenges in managing urban social–ecological systems and proposes that these can more effectively be addressed by collaborative networks where public, civic, other actors contribute unique skills and abilities. Paper II and Paper III study water resource governance in Bengaluru, a city that has become dependent on external sources while its own water bodies become degraded and depleted.Paper II analyzes how locally based ‘lake groups’ are able to affect change through co-management arrangements, reversing decades of centralization and neglect of lakes’ role in Bengaluru’s water supply.Paper III uses social–ecological network analysis to analyze how patterns in lake groups’ engagements and collaborations show better fit with ecological connectivity of lakes.Paper IV employs sense of place methods to explore how personal bonds to a site shapes motivation and goals in waterfront stewardship in New York City. Finally,Paper V reviews literature on stewardship and proposes a conceptual framework to understand and relate different uses and underlying epistemological approaches in the field. In summary, this thesis presents an empirically grounded contribution to how stewardship can be understood as a human–nature relation emergent from a deep sense ofcare and responsibility, knowledge and learning about how to understand social–ecological dynamics, and theagency and skills needed to influence these dynamics in a way that benefits a greater community of humans as others. Here, the care dimension is particularly important as an underappreciated aspect of social–ecological relations, and asset for addressing spatial and temporal misalignment between management institutions and ecosystem. This thesis shows that care for nature does not erode just because green spaces are degraded by human activities – which may be crucial for promoting stewardship in the Anthropocene.