The Smart City (SC) constitutes an imagined future city that achieves improved public service efficiency through technological development. However, the answers to how a smart city approach can contribute to urban sustainability still need to be clarified.Therefore, this study examines smart city development as a solution for urban challenges by comparing smart city services in two countries, Korea and Japan. Smart city initiatives and plans from local governments were collected from 16 cities in Korea and 20 cities in Japan.At the same time, major urban issues for both countries are identified in physical, economic, social, and environmental dimensions. The linkage between urban challenges and smart city services is visualized with a network graph. The results show that the majority of the services are relevant to spatial and environmental urban challenges. Also, the use of big data and AI is dominant. Smart city approaches can help local governments to overcome the lack of resources in the era of population decline and aging society and enhance urban safety issues.