Sustainability remains a key challenge in public health. The perspective article by Fagen and Flay adds to our understanding of technical factors associated with sustaining health interventions in schools. In this commentary, the Fagen and Flay article (2009) is considered within the broader literature on sustainability. By taking a broad view, public health theory and practice might be advanced further. Fagen and Flay illustrate that we have much to learn about sustainability. Questions for future research include: (a) what can we put into place at the systems level to ensure that the short-term efficacy of interventions have a fighting chance to be sustained? (b) considering the challenges inherent in sustainability, what are realistic goals against which to evaluate the cost-effectiveness of interventions found effective in the short-term? and (c) what theories, methods, and strategies in fields outside of public health can be drawn upon to improve work in public health? [For a response to this article by Fagen and Flay, see EJ826345.]