The role of "academic partners" working alongside teachers is an increasingly complex and sometimes controversial one. This article explores the role of academic partners in "Educational Action Research," reporting on data from a larger study conducted in New South Wales, Australia. Schools involved in the study had received targeted government funding between 2006 and 2010 to conduct school-based action learning projects employing action research. As part of the funding, the schools had been provided with external support from university-based academic partners, who supported individual school teams in the completion of their projects. Here we focus specifically on the role of the "academic partner." Data were obtained via semi-structured interviews with academic partners themselves, with the project's state coordinators who oversaw the project, and with teachers who had worked with the academic partners over the course of their school-based projects. Participants in the study identified significant benefits for both teachers and academics engaging in co-inquiry, but findings also suggest that the role of academic partner is increasingly complex, multifaceted and sometimes under-supported. When there is "good fit" between academic partners and schools and when structures are in place to support academic partners in their work, the academic partner role in schools can contribute to sustained educational change. In this article we discuss the crucial antecedents, enablers and constraints which ensure that academic-school partnerships enrich learning for both academics and teachers, building mutual capacity.