I.SEOUL.U that represents Seoul, the capital city of Korea, is a citizen-driven city brand created by Seoul citizens, through the citizens’ voluntary participation with their ownership mind. The brand unites meanings and images of coexisting Seoul where everyone lives an affluent lifestyle, passionate Seoul and leisurely Seoul. The development of I.SEOUL.U, from its naming to design, was based on citizens’ ideas and was approached using the collaboration concept between citizens and experts. There were many difficulties in the development of a qualified city brand for a capital city due to many newly attempted processes.