In the process of urbanization in South Korea, the concentration of population and economic activities in Seoul and its metropolitan area continues. Consequently, the gap between the Seoul Capital Region and non-capital regions is deepening. The central government has implemented various policies with the goal of achieving national balanced development, but the necessity and effectiveness of a balanced regional development agenda between the Seoul Capital Region and non-capital regions remain subjects of ongoing debate. In this context, this study analyzes the regional disparities between the capital region and non-capital regions and evaluates the introduction and implementation of South Korea’s national balanced development policies since the 2000s. The Roh Moo-hyun administration, from 2003 to 2008, demonstrated a strong commitment to national balanced development through the relocation of central administrative functions and state-owned enterprises to non-capital regions. However, since 2008, the Lee Myung-bak administration has actively pursued regulatory relaxation and economic efficiency in the Seoul Capital Region, seeking balance through market mechanisms. This policy direction has persisted through several changes in administration. Throughout this process, this study compares demographic, socioeconomic, and industrial characteristics between the Seoul Capital Region and non-capital regions and discusses the causes of regional disparities. Drawing from the lessons learned from South Korea's policy experiences, this study can suggest policy implications for achieving balanced development between regions in a developing country.