Modern industrialized economies have been dominated by service sector industries. In this regards, the portion of service sector in industry is growing faster recently. According to this movement, manufacturers try to combine the intangible service with their existing tangible products to fulfill specific customer needs. It has been called as concepts of “servitization” or “Product-Service System(PSS).” In other words, manufacturers are facing new opportunities that lead them to maintain sustainable competitive advantage. Companies should also attempt to utilize “service innovation” constantly for creating new services or improving existing services in order to satisfy the unique needs of customers. The objective of this study is to find the key success factors of four companies which did successful service innovation. First, this paper introduces the concept of Product-Service Systems and servitizaiton and presents four companies based on classification framework of Shumenner’s service process matrix. Second, this paper analyzes four business models of companies through the binding platform of buyer utility map and value curve. Finally, this paper derives common and unique key success factors from four business models for creating new added value sources, competitive edge and sustainability.