Higher education is widely recognized as a pivotal factor in supporting the implementation of sustainable development goals (SDGs) through research, teaching and learning, collaboration, and management governance. Therefore, this research aimed to analyze the impact of leadership styles on academic performance, examine relational capital as a mediator in the relationship between leadership styles and academic performance, investigate the effect of sustainability leadership on curriculum design, and assess the influence of curriculum design on academic performance. The population consisted of lecturers from the Faculty of Economics at State Islamic Universities in Indonesia, the Islamic Science University of Malaysia (USIM) in Malaysia, and the Faculty of Islamic Studies, Department of Sharia and Economics, at the University of Malaya. With a population of 783 individuals and a precision of 5%, the sample size was determined to be 265 lecturers, and Partial Least Square (PLS) was used to test the hypotheses. The results showed that sustainable leadership did not affect academic performance. Furthermore, relational capital mediated the relationship between sustainable leadership and academic performance. Sustainable leadership and curriculum design directly affected academic performance. The findings highlighted the crucial role of leadership in facilitating curriculum design, relational capital, and academic performance. By emphasizing relational capital, higher education institutions proactively enhanced academic performance. Future research should also consider other important factors related to academic performance and explore different behavioral effects and leadership styles.