Sustainable entrepreneurship has recently been identified as a promising force to push a sustainable business paradigm shift. A key challenge for researchers and practitioners is thus to understand and promote such practices. However, critics have argued that sustainable entrepreneurship research is heavily reductionist, in the sense that it assumes an independent and rational entrepreneur, with an exclusive focus on entrepreneurial individuals and opportunities. In this paper, we problematize these assumptions and offer an alternative theory of sustainable entrepreneurship based on ethics of care. We introduce the individual-care nexus, where individuals are assumed to be dependent, emotional, and relationally connected. This theoretical development leads to new ways to more accurately grasp the nature of motivations, emotions, traits, and practices in sustainable entrepreneurship. We illustrate our theory with an empirical case of a sustainable entrepreneur within the Green IT movement in Sweden between 2012 and 2017. We argue that our theoretical take on entrepreneurship can both advance research in sustainable entrepreneurship and provide sustainable entrepreneurs with a better understanding of their practices and a new vocabulary.