Establishing interdisciplinary academic departments has been a common response to the challenge of addressing complex problems. However, the assumptions that guide the formation of such departments are rarely questioned. Additionally, the designers and managers of interdisciplinary academic departments in any field of endeavour struggle to set an organisational climate appropriate to the diversity of their members. This article presents a preliminary analysis of collaborative dynamics within two interdisciplinary university departments in Australia focused on sustainability. Social network diagrams and metrics of coauthorship and cosupervision are analysed qualitatively. A "vicarious interdisciplinarity" was identified among key academics working narrowly in order to earn the resources that allow them to support others working interdisciplinarily. Those supported in this way appear to benefit from the esteem and nonredundant collaborative connections their mentors provide via this strategy, but they experience uncertainty about their own career opportunities in similar settings. This article thus unearths a conundrum of succession for interdisciplinary academic environments, and suggests that simple colocation of diverse academic stars is an inadequate strategy to achieve effective intradepartmental collaboration.