The term “sustainable development” is rhetorically useful to many different actors because it is ambiguous and multi-vocal, offering a frame that glosses distinct and even conflicting meanings as similar. The discursive field of sustainability is structured by plurality in the terms of (usually unspoken) reference to what is to be sustained – environmental quality; the profitability of a business enterprise; the budgetary/political health of a governmental or non-profit entity; or a wider community and its economic, social and cultural wellbeing. Each of these represents a different definition of the problem and direction for seeking solutions. Each aims at a distinct bottom line in strategic thinking about sustainability. Approaches to sustainable development in which one or another of these goals is prioritized come from different institutional and social bases with unequal links to power. Here I will present some ethnographically based observations on the various ways that sustainability is conceptualized by a range of social actors in one medium-sized American city, and how these meanings mingle in the discursive field of sustainable development. I will also offer some thoughts on using this kind of locally based material for teaching critical analysis and effective activism in the classroom.