The world is faced with unprecedented global economic, environmental, and social challenges. Sustainable development has emerged as an organizing principle for addressing these issues. Corporate social responsibility (CSR) is seen as the business contribution to sustainable development. The article defines CSR as an organization's efforts to secure resources and legitimacy for survival or competitive advantage by managing nonmarket and nonregulated issues arising from complex social and environmental problems. Supporting this definition, the “sustainability issue management” (SIM) model is presented to help managers and researchers assess and manage CSR issues. Based on ecological economics, the tool originated from a larger study. The model is used to explain and discuss how the UK Government's National Indicator 185 (requiring carbon reporting from Local Authorities) shaped the action of a supplier to Local Authorities. The case illustrates how the SIM model can help both managers and researchers understand and manage CSR issues.