This study, with its practical implications, is a valuable resource for organisations. It examines the impact of Sustainable Management Accounting (SMA) practices on the implementation and effectiveness of Sustainable Corporate Governance (SCG) within organisations. It also investigates the various dimensions of SMA and explores the mediating roles of the Internal Control System (ICS) in the relationships between SMA and SCG. The empirical data, collected from 512 individuals across India using a purposive sampling technique, represent a diverse cross-section of the population, including shareholders, investors, finance officers, executives, and professionals such as chartered accountants, lawyers, bankers, and company secretaries. The findings of this study are actionable, indicating that SMA has a positive and significant impact on SCG. Furthermore, it was found that SMA is influenced by factors such as the accounting system, reporting method, transparency policy, and stakeholder involvement. Moreover, the results suggest that companies with well-developed sustainable accounting systems have enhanced ICS and corporate governance metrics, which in turn result in improved board oversight and stakeholder engagement. Finally, the outcome of this study not only assists in developing sustainable corporate governance through sustainable accounting management but also contributes to the UN’s sustainable goals through accounting and governance in the corporate culture and approach.