Based on its advanced information and communication technologies (ICTs) and construction industry, Korea has developed an ICT-driven smart city called Ubiquitous Cities (U-City). One of the strategic adopters of this concept is Sejong City, which is being developed in central South Korea as a new administrative city. Besides being different from the European model of a smart city, Smart Sejong City is one of the full-scale greenfield development models of a future city armed with cutting-edge ICTs. From the beginning stages, high levels of ICT infrastructures were facilitated together with urban integrated information centres (UIICs) and devices for service provision. In addition to transportation and public safety services, smart community design that is derived from citizens’ needs and a zero-energy community strategy for environmental contribution are under development. In this chapter, the background of Korean smart cities and contents of the Sejong Smart City are presented in terms of viewpoint of industry-mix, infrastructure, technology and services, followed by discussion on the future of the smart city.