Through the UN 2030 Agenda adopted by the United Nations, sustainable development is bringing about many changes around the world. While discussions continue on the roles of libraries in supporting sustainable development in library communities, specific discussions on this have not been made enough. This study reconsidered the roles and functions of libraries to support sustainable development and discussed approaches to which libraries can perform in terms of informational, social, cultural, and environmental aspects. It also proposed a plan to allow libraries and librarians to lay the groundwork for supporting the sustainable development of society by reconsidering the roles of librarians as the core of all library activities to support sustainable development.