We expand on the emergent research of an ethic of care (EoC) to theorize why and how an organizational EoC fosters employee involvement in sustainability‐related behaviors at work. Across two studies, we explore the socio‐psychological mechanisms that link an EoC and involvement in sustainability‐related behaviors. The results of Study 1, in which we applied an experimental design, indicate that an EoC is significantly related, through employees' affective reaction towards organizational sustainability, to involvement in sustainability‐related behaviors. In Study 2, in which we used time‐lagged data, we further drew on social identity theory to suggest that an EoC is both directly and indirectly, through enhanced organizational identification, related to employees' satisfaction with organizational sustainability. Through these two mechanisms, we explain the process by which an EoC can drive employee involvement in sustainability‐related behaviors. These theoretical developments and empirical findings help to better understand the micro‐foundations of organizational sustainability by building upon the moral theorizing of care.