Research into how HR contributes to organisational performance is plentiful yet plagued by challenges. Alongside the 'black box' issue between HRM and performance, the time-lag effect and the range of performance indicators applied, the role of the HR department in this relationship is critical although often ignored. A longitudinal case study is presented here that focuses particularly on this issue, and shows a complex picture of improving HR department importance alongside high-level financial performance, but declining employee commitment and morale. The article suggests that the tensions between the rhetoric of HRM strategy, the grim reality of the employee experience and a lack of focus on human capital meant the outstanding financial performance was not sustainable in the longer term. The inherent conflict in serving both management and employees in process-and people-orientated roles is highlighted.