<p>Customer service is considered as an integral and essential component of the firm’s marketing strategy and a means for competitive advantage. It represents a way by which a firm can go the extra mile to achieve customer satisfaction and loyalty. This study therefore investigates the extent to which the customer service process comprising of pre-transaction, transaction, and post-transaction influence customer satisfaction and loyalty. 251 customers of the five top banks in Nigeria were surveyed in a cross-sectional survey using a structured questionnaire. Analysis was carried out using SMART-PLS-4 to test the hypotheses. The results revealed significant positive relationship between transaction customer service process and customer satisfaction, and post-transaction customer service process and satisfaction. However, no significant relationship was found to exist between pre-transaction customer service and satisfaction. The mediation result also shows the significance of customer satisfaction in mediating the relationship between customer service and loyalty. Consequently, customer service process can be a pragmatic approach to achieve customer satisfaction and loyalty. Therefore, banks and other service firms should consider these three crucial steps in the implementation of customer service for improved served service quality and competitive advantage. Implications and suggestions for future research were also proffered.</p>