The smart city is a modernization effort that enables cities to use their resources more effectively and to provide better services to their residents. In this study, the smart practices of Kashiwanoha City, Japan, one of the best smart city examples in the world, were examined. The study showed that smart environment applications are designed to improve the quality of life of the citizens and ensure the sustainability of the city. The smart environment applications in Kashiwa-no-ha Smart City include smart mobility, smart technology, smart governance, smart economy, smart living, and smart environment based on transport, energy, and environment. The integration of blockchain technology is a potential solution to address the challenges of urbanisation in smart sustainable city development. The development of Kashiwa-no-ha Smart City is an example of how cities are linking their technological policies and development plans to achieve development while linking the objectives and dimensions of sustainable development to provide the best possible benefit from the available technologies. The most important factor behind Kashiwa-no-ha‘s success is the cooperation of the public and private sectors and universities. For successful smart city practices, it has been proposed to establish an independent organisation similar to the Urban Design Centre Kashiwanoha (UDCK) with a separate budget and decision-making power.