Abstract
Interactionist theories link individuals' work performance to both situational and personality factors. However, while prior research finds support for the direct effects of both employees' situational experiences and their personality on performance, empirical support for their interactional effects is lacking. This article first examines how supervisory support influences employees' self-concept and in-role performance. Second, it investigates how perceived organisational support (POS) moderates the effects of supervisory support on employee self-concept and how employee self-concept mediates the relationship between supervisory support and employee in-role performance. Using a sample of 215 professional employees drawn from knowledge-intensive organisations in New Zealand, findings suggest that supervisory support relates positively to employees' self-concept. Moreover, this relationship is strengthened when POS is stronger. The study also finds employee self-concept plays a partial mediating role in the relationship between supervisory support and employee in-role performance. These findings and their implications for research and practice are discussed.