This study examined the extent of a strategic approach to human resource (HR) management in small and medium professional service firms, and if it is used to develop intellectual capital (IC). Data were collected from 165 Australian professional service firms. Path analysis showed that HR involvement and the adoption of a collective set of strategic HR practices contributed positively to IC levels (particularly human, social and organizational capital). IC acts as a mediator between HR practices and firm performance. HR practices alone did not increase the performance of the firms studied. The findings are unique in the context of studies on small- and medium-sized professional service firms in that a holistic approach to assessing both HR practices and all IC components was taken rather than examining the individual construct relationships. In the context studied, HR influence is critical to increasing IC.