Organizations in disaster management system should learn from previous experience and strategically use their lesson for the refinement of a system’s competencies for risk management. However, the MV Sewol incident revealed the absence of the organizational learning in the Korean disaster management system. With mixed methods of content analysis, in-depth interview, and social network analysis, this study identified key failure factors in response to the incident and categorized them by managerial, structural, and institutional domains. While the Korean government took bold steps to rebuild its risk management system, those efforts were biased to structural reforms and lacked fundamental changes in human and informational resources management. Based on the findings, this study suggests the balanced efforts for system refinement for effective risk management.