This paper presents a review of the relationships between information technology and customer relationship performance, employee user satisfaction, employee service quality and customer satisfaction. An extensive literature research is conducted to answer three research questions about the roles of information technology in the context of customer relationship management, the effect of information technology on front-line employees’ user satisfaction and service quality, and the impact of user satisfaction of information technology on employee service quality and thus customer satisfaction. A mechanism how information technology affects the two key parties in the front-line business process, customer service employees as well as customers, is discovered along with the answers to the research questions. CRM technology, representing customer-related information technology, is mainly discussed in the paper. The role of CRM in customer service is explored from the role of the relational information processes and technology use in customer relationship performance; the mediating effect of customer knowledge and the moderating effect of supply integration is reviewed. Sales force automation (SFA) as an operational CRM technology is also examined of its role on customer service in terms of five levels. Ineffective interaction of relationship information processes and CRM, insufficient supply chain integration, and organizational and contextual elements are the factors of CRM technology malfunction. Needs theory and equity theory are used to discuss the impact of information technology use on employees’ user satisfaction. Service profit chain (SPC) theory is used in understanding the impact of user satisfaction on employee service quality, moderated by employees’ embodied service knowledge. Finally, the impact of service quality on customer satisfaction is found mixed in many researches.