The article focuses on collective knowledge formation processes in which an understanding of sustainable public administration (PA) is constituted. We turn the perspective from the production of sustainability data to the epistemic aspects of sustainability: to justifications, rationalities, and knowing in the specific context of sustainability management in public organizations. We approach sustainable policymaking as an ambiguous and complex process that requires collective sense-making of what public organization is and desires to be. This process may lead to a reconsideration of organizational identity, especially concerning core values, purpose and expectations of PA. Through a scoping review of the organizational identity literature, we explore what is known about identity construction and identity work in the PA context. The results of this review will provide insights to further analyze what sustainable PA means through the lens of organizational identity. We suggest that, as an ambiguous policy aim, sustainability will describe the new mission of PA and set strategic ambitions for transformation. In public organizations, identity construction can be used as a tool for collective sense-making and knowledge formation that responds to the critical strategic questions of why PA exists, what it should achieve in the future, and how its tasks are prioritized. The article contributes to sustainability management discussions by linking public and knowledge management studies and extending the understanding of sustainability as a strategic aim in both fields of research.