This study utilizes data from Chinese A-share listed companies from 2010 to 2020 as research samples to explore the impact of CFOs serving as board secretary on the quality of information disclosure, financing constraints, and enterprise sustainable development performance. The empirical results indicate that CFOs holding the additional role of secretary of the board significantly enhance the financial performance and environmental and social responsibility performance of companies. The quality of information disclosure and financing constraints act as mediators between the dual role of the CFO and sustainable development performance. Heterogeneity analysis finds that in non-state-owned enterprises and small and medium-sized enterprises, the effects of CFOs serving concurrently as secretaries of the board on improving financial performance, environmental social responsibility performance, information disclosure quality, and alleviating financing constraints are more pronounced. The findings of this study delve into the impact of the dual role of CFOs on sustainable development performance, enrich the literature in the relevant field, and provide valuable theoretical basis and practical guidance for the selection and appointment of corporate executives, tailored for journal publication requirements.