This study analyzed the process of introducing the system of Public Agency for Social Service policy, which began as a pilot project in 2019, from the institutional perspective. This policy of directly providing social services in the public sector came to the Moon Jae-in government and emerged as a major change in the service delivery system. Stakeholders surrounding the Public Agency for Social Service policy showed that the positions of related facility associations and heads of institutions, which were vested rights, and workers and unions, which were vested rights. In terms of social environment, social care has become a request of the times and has been announced as a national task. In the process of institutional formation, social interaction factors and political interaction between stakeholders are important changes. As the system changes, the intended and unintended consequences occur at the same time. Improving publicity and improving the treatment of workers are the intended results, but deterioration in service quality and public inefficiency can be negative. Efforts must be made to make decision governance so that the intended results of the Social Service Center policy can be achieved.