In this article, I present an analysis of professionalism as defined and enacted by the History Teachers' Association of New South Wales (HTANSW). This analysis was part of a larger doctoral project (2000-2005) in which I employed critical qualitative inquiry to compare and contrast the contribution that two subject teaching associations (science and history) make to the project of teacher professionalism in Australia. My aim for this project was to explore what professionalism means in practice for a unique group of teachers: those who have made an active and fundamental commitment to their subject community by voluntarily serving on the executive committee of their subject-based professional association. In this article, I present findings from the case account of the HTANSW--an organization that operates locally as a professional teacher community and a representative organization for school-based history teachers. This case account details the maneuverings of an association that powerfully asserts an expansive role for history teachers as both contributors to, and critical commentators on, curriculum policy. In this article, I conceptualise the actions of this association as an enacted form of teacher professionalism. Drawing on study findings, I explicate my conception of professionalism as an enacted discourse of power and I show how this discourse is enacted in subject-specific ways.