In 2013, the Mori Memorial Foundation in Japan announced Seoul as the 6th most competitive city around the globe. This result draws attention to the Korean capital’s success as a genuine global city in this modern era. In managing a city of this size, it can be well expected that numerous conflicts of interests and other legal issues occur when establishing and implementing public policies. Therefore, it becomes necessary for the Seoul Law Department to provide adequate legal advice and to settle legal disputes when the city’s public officials are performing their administrative works. This paper examines the management planning for an advanced local government’s law department and specifically addresses some policy implications for Seoul’s local government. In doing so, we studied the current operation conditions for Seoul government’s scattered Law Department, focusing on its organizational structure and its main duties. We further examined major setbacks currently faced by the Seoul Law Department, as categorized by units or tasks. Using the New York City Law Department as a model and studying its organizational structure and duties as reported on its annual reports, we deduced some implications that we considered important for efficiently organizing a law department. Finally, we suggested some detailed plans to improve Seoul’s legal support system that take into account both Seoul Law Department’s current status and the lessons deduced from the New York City Law Department. These plans include legal support reinforcement and the expansion and management of the law department affiliates. It would be essential to implement efficient public service through organized internal processing system in such a big government of Seoul, considering Seoul’s immense financial and social capacities as well as its large population. This paper aims to provide detailed plans for building an integrative legal service system that can offer a ‘one-stop’ legal service to the city and its related subjects. We hope this paper could contribute to the introduction of a more efficient legal support system for Seoul government that would enable a systemic and comprehensive policy realization for the benefits of the Seoul citizens.