Middle school leaders are increasingly playing a crucial role in developing and maintaining the nature and quality of pupils learning experiences. However, there is often ambiguity about their role, sometimes experienced as being caught in the "crossfire" between the expectations of different levels in the schools' hierarchy. Ensuring good teaching and learning was universally recognised as being at the heart of the middle leader's work, but this also created some of their most intractable problems particularly the rival expectations of monitoring and collegiality. This paper critically analyses the role, purpose and development of middle leaders and specifically the assistant principal, which is a key leadership position within the NSW Department of Education and Communities (DEC). The professional learning needs of middle leadership roles are considered through a critique of two middle leadership development programs currently in place in Sydney, NSW. The Australian Institute of Teaching and School Leadership (AITSL) standards are assessed for their relevance and applicability to middle level leadership development. Finally, a professional learning model to build the leadership capacity and skills of assistant principals is proposed. Overall, this article suggests that the development of middle leadership preparation programs in schools is now more important than ever.