This study examines determinants of the service expertise and service quality of customer service representatives (CSRs) working for call centers which have become a firm’s typical service encounter. More specifically, as such determinants, the study proposes customer knowledge accumulated in electronic knowledge repositories (EKRs) as a digital knowledge source along with expertise location as a human knowledge source. Moreover, the study considers technological IT resources (TIR) as another determinant of CSRs’ service expertise and service quality. Finally, the study examines the relationship of service expertise and service quality. A total of 292 responses were collected from CSRs working at call centers and were used for the analysis. The key findings are as follows: first, customer knowledge in EKRs, expert location and TIR considerably increased CSRs’ service expertise. Second, customer knowledge in EKRs and expert location were positively associated with service quality, but TIR had no significant effect on service quality. Finally, CSRs’ service expertise greatly enhanced service quality. The results imply that CSRs’ service expertise and service quality depend on knowledge sources and IT resources provided by the call center.