This paper describes how two primary head teachers, nationally recognised as role models for the development of an education for sustainable development (ESD) in their schools, manage the implementation of this area. In doing so, it shows how they adopt two very different approaches to ESD and to their job generally, and suggests that whilst there are some commonalities between them, educational leadership needs to be seen as driven by a moral purpose, engaging and re-engaging with each situation, entering into a dialectic with others' visions, leading to the re-conceptualisation of problems in different ways. This not only suggests a continued tension between such uniqueness and standardised approaches to headship, but raises questions about current policy imperatives for developing models of sustainable leadership.