This chapter explores how corporate sustainability has been addressed in Japan. The Japanese companies’ awareness of the environment has been high, especially since the 1990s, promoted by the government’s various policies. However, all these policies are non-statutory, while the traditional corporate law theory has been reluctant to acknowledge corporate social responsibility (as the issue has traditionally been known). More recent reform of corpgovernance risks. This is despite the fact that the primary focus of the reform has been on the shift to the shareholder primacy idea, departing from the traditional stakeholder-oriented corporate governance of Japanese companies. With these complexities, it is anticipated that corporate sustainability will become a commonly acknowledged issue of corporate governance in Japan in the coming years.orate governance, facilitated through the implementation of the Corporate Governance Code and Stewardship Code, acknowledges the significance of sustainability and environmental, social and