Applying networking and connectivity to empower human resources and infrastructure towards the formation of sustainable regional service ecosystems is becoming increasingly important for well-being of people within and outside society to meet social challenges. However, the concepts of smart city (SC) for residents/citizens and smart tourism destination (STD) for visitors/tourists are not yet well coordinated. Therefore, this research provides a framework for regional innovation through “smartization”, which is common to both SC and STD. The framework is constructed from the perspective of the service ecosystem and applied by analysis of four case studies: The framework is constructed from the perspective of the service ecosystem and applied by analysis of four case studies: two representative smart city projects (“urban policy”-directed type) (Toyama and Aizu-Wakamatsu), and two advanced tourism projects (“resource integration”-directed type) in Japan and Slovenia. Based on these examples, the framework clarifies the macro aspects of human resources and infrastructure’s roles with data platform and presents a smartization model with service layers and dynamic spiral through integrating to the concept of Smart Tourism City (STC): a city that aims to improve/create QoL (quality of life) and QoE (quality of experience) for citizens and tourists. It is expected that further STC-concept-based research towards building the quantitative model will lead to concrete insights into the typology of holistic servitisation of each city or region.