The purpose of this study is to offer operational, policy guidelines for slogan development by examining what differences there are when Seoul city brand personality is compared with the slogans of other major cities, and by deducting strategic implications and undertones of city branding. Documentary research was conducted centered on discussions related to city branding, city brand slogan studies, personality of city brand slogan, and city branding of Seoul. In order to measure personality of Seoul and each city brand, an empirical study was implemented in which the slogans were exposed to the subjects and the responses were measured. As a result of study, a yardstick to evaluate overall activity of city branding and the promotion system were established, and plans to utilize it for city branding of Seoul were considered; and, by establishing the Seoul city branding committee having taken counsel from academia and industry, supervision of the related task by the committee was proposed. This study has significance for its proposition of policy implications of city branding of Seoul in order to unfold differentiated positioning, and customized branding strategy by target.