There is increasing attention on how universities assess and address mental health and wellbeing among staff and students. Surveying population-level mental health and wellbeing in higher education is a significant methodological challenge. In this article, we present a comprehensive, multi-faceted, and multi-level approach to mental health and wellbeing-related measurement through institution-wide survey research. The approach measures high-level institutional factors (the overarching psychosocial safety climate [PSC] of a university), medium-level psychosocial factors (risk and protective factors relating to study or work), and ground-level individual factors (mental wellbeing, emotional exhaustion, and engagement). We collected and analysed data over three years at one Australian university (n=7,459, comprising 4,682 staff and 2,777 students). In a world-first comparison, across 20 university areas, we found that PSC was negatively related to emotional exhaustion among both staff and students. Moreover, emotional exhaustion among university staff was positively related to emotional exhaustion among students. Through multi-year data collection and analysis, we educated institutional stakeholders on the complex, multi-level, and collective nature of mental health and wellbeing in higher education. Consequently, there is high-level decision-making in train to make PSC a key performance indicator for the institution. This evidences knowledge translation and mobilisation. It also reflects a paradigm shift at the level of university leadership, re-orienting toward an upstream, proactive approach to assessing how institutional conditions shape mental health and wellbeing – rather than retaining a downstream, responsive approach that relies on measures of psychosocial injury, mental ill-health, and support-seeking.