Aim This paper aims to identify and explore key obstacles preventing ward managers from effectively performing the human resource management (HRM) responsibilities required in their role. Background In the context of increasing costs and the decentralisation of responsibility to ward level, the relevance of the ward manager role within the 'black box' between human resource management and firm performance is becoming increasingly pertinent. Methods This paper presents an intensive case study including 37 interviews across all levels of a hospital where senior management attempted to shift to a high performance model of human resource management. Results The findings indicated that ward managers played a critical role in maintaining and improving employee performance, although they were restricted from effectively performing their responsibilities due to budget pressure and limited managerial skill development. Conclusions Our findings support the contention that hospitals would benefit from focusing on the critical role of the ward manager as the central locus of influence in high performance human resource management (HPHRM) systems. Implications for nursing management Investment into high performance human resource management is discouraged if the hospital cannot adequately enable ward managers who are responsible for implementation. Introduction of managerial skills training to potential and existing ward managers is critical.