While it is well known that SME owner–managers’ sustainability values and attitudes impact their company’s sustainability activities, they often face profit-driven institutional orders. In a qualitative study, we investigate which identities are critical for their engagement in sustainability and how these identities interrelate with their institutional environment. We applied a qualitative design with narratives from 29 owner–managers of hospitality businesses who belong to a New Zealand-based sustainability network. Our study revealed no single overarching sustainability identity; instead, six identities could be identified as sustainability-related and be linked to different institutional orders. By analyzing the interplay between the identities and the institutional environment, we also found mechanisms on how SME owner–managers impact on their business’ sustainability. We revealed that an adequate institutional environment can foster the development of sustainability-related identities, which in turn can lead to cultural evolution towards more sustainability. By integrating identity theory with organizational institutionalism, we contribute to theoretical development and to further sustainability research at individual and institutional level.