Promoting products and companies as both socially and environmentally sustainable is a core component in many contemporary marketing strategies and increasingly the concern of many consumers. While the effects of corporate social responsibility on consumer perception and firm performance have been widely investigated, research has yet to explore how and why these expectations themselves change over time. In this study, I use institutional theory and the theory of structuration from sociology to evaluate the shift in norms regarding environmental responsibility in the United States over a thirty-year period. A qualitative and quantitative content analysis of newspaper articles shows that environmental discourse has shifted from an emphasis on protection of the environment against toxic, modern encroachments, to a set of frames that emphasize the efficiency of technology and efficient use, if not improvement of, the environment. The stakeholders held responsible for protecting the environment have also changed from government actors to company and consumer stakeholders. These findings help to reveal the discursive underpinnings of CSR perceptions at a societal level and have implications for conceptualizing the legitimation of environmental corporate practice.