Recent curriculum reform in history in Australia promotes "historical understanding" through discipline-based teaching practice. However, many middle school teachers are new to the scope of historical knowledge and skills required. This paper reports on a case study of five Queensland teachers in one secondary school who undertook a school-based trial of the Year 8 Australian Curriculum: History in 2012-2013. Drawing on notions of historical consciousness and frameworks for curriculum alignment, the case study indicates that the intent of the stated curriculum to develop concepts of "historical understanding" is undermined by two factors--first, teachers' inadequate knowledge of the scope of the curriculum and second, a patchy understanding of how key substantive and procedural historical concepts contribute to "historical understanding". The research identified significant gaps in the disciplinary knowledge of history teachers and makes recommendations for pre-service and in-service history teacher education.