This study elucidates how Organic Seed Alliance (OSA), a non-profit organization (NPO), manages and governs its activities to protect crop diversity in the United States. The results of interviews with OSA’s members were analyzed based on corporate governance theory. The conclusions result from two perspectives: management and governance. Regarding management, recruiting members who have different types of knowledge and experience levels, leads to formulating appropriate strategies and plans. The process of devolving decision-making authority to local branches enables collaboration with stakeholders for improved organizational performance. Regarding governance, the board of officers is the highest decision-making body and is responsible for guiding and securing the managers and staff throughout the organization. In addition, informal governance by stakeholders can drive the activities of OSA toward conservation of crop diversity.