In order to realize the benefits of ITSM, it is necessary to institutionalize ITSM into the organizational culture. Currently, efforts to routinize ITSM lack in practice, and research in this area is also lacking. This study identifies the factors affecting the routinization of ITSM through literature review and interviews with experts, selects a company that has successfully routinized ITSM, and analyses the activities, methods, and procedures employed by the company on the factors in detail. The specific factors analyzed in the study include fulfillment of the customer requirements, top management support, communication, change management, training and education, quality of the ITSM system, and capability of the personnel. Important points verified in this study is that in order to realize organizational performance from ITSM, just the adoption of ITSM is not enough, but the routinization of ITSM through continuous and systematic management and improvement with the support of top management are required. Since this study is a descriptive case study, results of the study cannot be generalized. However, the study will provide practical information that can be referenced by the organizations attempting to routinize ITSM. In addition, results of the study will provide a basis of future research in ITSM.