Employee performance attainment is a pervasive issue in the workplace and is increasingly becoming an important problem for effective human resource management. A review of the extant literature on perceived organizational support (POS) and performance suggests that there is a dearth of research aimed at examining the underlying mechanisms and the boundary conditions of the relationship between POS and performance. One of the objectives of this study is to examine the mediating role of psychological capital on the relationship between POS and performance. Furthermore, this study investigates the moderating role of organizational justice perception in said indirect relationship. Study 1 included a sample of 465 employees from both large private life insurance and telecom organizations. Study 2 was conducted on a sample of 216 employees from a large steel manufacturing firm. Findings suggest that psychological capital mediated the relationship between POS and performance. The indirect relationship of POS and performance via psychological capital was moderated by organizational justice. However, there is a counter-intuitive finding in this research. It was observed that at a high level of organizational justice, it had a smaller effect on performance in contrast to low level of organizational justice. Finally, theoretical contributions and managerial implications are discussed.