A competitive higher education environment marked by increased accountability and quality assurance measures for doctoral study, including the structured training of doctoral supervisors, has highlighted the need to clearly articulate and delineate the work of supervising doctoral students. This article responds to this imperative by examining the question: in the contemporary university, what do doctoral supervisors "do" and how might their work be theorized? The response draws on life history interviews with doctoral supervisors in five broad disciplines/fields, working in a large metropolitan university in Australia. Based on empirical analyses, doctoral supervision is theorized as "professional work" that comprises five facets: the learning alliance, habits of mind, scholarly expertise, "techne" and contextual expertise. The article proposes that this model offers a more precise discourse, language and theory for understanding and preparing for the work of doctoral supervision in the contemporary university.