["Business Ethics, the Environment &Responsibility, EarlyView. ", "\nABSTRACT\nGreen Building Social Movement Organizations encourage the adoption of green buildings, primarily by promoting sustainability rating tools. While numerous papers have explored the market impact of these sustainability rating tools, very few have examined either the lengthy and protracted process of their selection and enrollment by organizations, or even their impact upon the structure and governance of organizations. This paper fills these gaps by presenting a 20‐year case study of organizational evolution. It identifies five distinct periods through which the chosen organization variously selected, developed, established, lost control, and transcended its relationship with LEED (Leadership in Energy and Environmental Design; a ‘green building’ rating tool) in Canada. Conceptually, our analysis has roots within the Sociology of Translation and (Scandinavian) Institutional Theory. In this, we treat the technical mediation of sustainability rating tools as institutional work activities to understand their role(s) in organizational evolution. The empirical basis for our analysis is data acquired through 21 semi‐structured interviews with organization founders and key personnel in each period, as well as a comprehensive analysis of archival records. Our findings offer significant insights for organizations that have bound themselves to a tool, certification, or standard as their means of market or societal transformation. We close by recognizing our study's limitations before underlining the crucial managerial and policy consequences of our analysis.\n"]