With the rapid development of information technology, customer relationship management systems (CRMS) have been widely adopted by banks and play a crucial role in customer development and retention. However, there are also numerous cases of CRMS implementation failures. Further, employees are enabled by CRMS to make service decisions with the support of leaders. The role of leaders in employees’ CRMS usage is understudied. Thus, based on the information systems diffusion model and the theory of leader substitutes, a research model is proposed and empirically tested. The results show that employee CRMS explorative usage has a positive impact on their service performance, while employee CRMS exploitative usage has a significant negative impact on service performance. Besides, significant leadership substitution effects are discussed in CRMS usage.