This article draws on theories of person–organisation fit and leadership behaviour to explore how supportive leadership is related to communication practices, collaborative working practices and performance management practices and how these three practices, in turn, relate to public servants’ job satisfaction. A model of supportive leadership's direct and indirect effects on employees’ job satisfaction is empirically tested using responses to a survey administered to the European Court of Auditors (ECA) staff. The findings show that communication and collaborative working practices mediate the relationship between supportive leadership and job satisfaction. Supportive leadership positively relates to performance management practices, but these practices have no significant association with job satisfaction. While addressing a theoretical void in the field, this study also makes an empirical contribution by unveiling how a professional European public audit institution manages its human resources and the means it uses. Points for practitioners: Elaborating on the relationship between leadership behaviour and person–organisation fit in the context of a supranational public entity helps to explain what motivates public servants. The relationship between supportive leadership and public servants’ job satisfaction is mediated by two organisational practices: communication and collaborative working practices. Transparent performance management practices do not mediate the relationship between supportive leadership and job satisfaction. Public sector organisations with professional staff can centre their human resource management around effective communication and collaborative working practices to ensure greater employee satisfaction in the workplace.