This international comparative study focuses on examining the impacts of Education for Sustainability (EfS) expertise and self-organization, as two aspects of EfS skills and knowledge, on personal and interpersonal outcomes, which is one of the EfS effective in-role performance dimensions. We collected data from 664 academics in Malaysia and Japan, screened the data, and utilized partial least square structural equation modeling (PLS-SEM) to test our model. Our findings indicated that both predictors were statistically significant and practically relevant in predicting the outcome variable. In addition, our permutation-based multigroup analysis revealed no significant differences between academics from the two countries in terms of the paths within the model. Notably, the model, based on estimation using the aggregate data, showed a medium level of out-of-sample prediction power. We also examined and interpreted country-specific results and suggested avenues for future research in EfS leadership.