This paper explores the repositioning of state curriculum agencies in response to the establishment of the Australian Curriculum and the key national policy organisation responsible for its development: the Australian Curriculum, Assessment and Reporting Authority (ACARA). I begin with an analysis of the federal Labor government’s role in the early years of the Australian Curriculum reform, arguing that Labor was afforded a rare window of political opportunity that enabled the fundamental restructuring of curriculum policy at the national level, and which has significantly altered intergovernmental and inter-agency relationships. Following this, I engage with research literature that has sought to theorise the changing nature of Australian federalism in relation to schooling reform. I then present an empirical analysis based on interviews with policy-makers in ACARA and curriculum agencies in four Australian states (Western Australia, New South Wales, Queensland and Victoria). My analysis draws attention to three dominant trends: powerful new roles for ACARA in driving national reform and inter-agency collaboration; increased policy overlap and blurred lines of responsibility; and an uneven playing field of intergovernmental and inter-agency relationships and powers. I conclude by considering the implications of emerging reform trends for conceptualising the shifting dynamics of federalism in Australia and beyond.