Customer Relationship Management (CRM) system implementation is a complex exercise in organizational transformation. Although companies spend a fortune on CRM packages and the implementation process, they still face various problems. This paper explains the CRM implementation process in a tower provider company, including identifying issues, implementation phases, and the business process based on Enhanced Telecom Operations Maps (e-TOM) framework. An in-depth single case study was conducted to analyze which critical success factors (CSF) are necessary. The results from the case study suggest that people, technology, and processes are the essential perspectives of CRM implementation. These perspectives are detailed into eight CSFs. The findings also recommend emphasizing CRM implementation as a business solution, not only an IT solution. The implementation process and the CSFs guide practitioners to plan and monitor CRM implementation and for researchers as a foundation for future research.