This paper examines the influence of the presence and proportion of executives with environmental backgrounds on corporate green R&D manipulation using data from Chinese private firms between 2010 and 2022. The results show that a higher representation of environmentally experienced executives on the board significantly reduces green R&D manipulation by attracting green investors and mitigating managerial short-sightedness. The governance effect is particularly strong in private firms with higher executive pay stickiness, stronger internal controls, and lower levels of green R&D subsidies. However, the effect diminishes in state-owned enterprises, where policy mandates and institutional constraints restrict managerial discretion, and in regions with stricter environmental regulation or entrenched industrial structures. Overall, the findings highlight that executives’ environmental backgrounds play a vital role in promoting sustainable innovation and reducing opportunistic behavior, though their effectiveness depends on ownership structure, institutional environment, and regional context.