Given the global challenge of increasing teacher attrition and turnover rates, the exploration of factors and mechanisms that improve teachers’ organizational commitment has become a pivotal topic in educational research. In this context, the present study examines the influence of teachers’ emotional intelligence on their organizational commitment, with a specific inquiry into the mediating role of teachers’ psychological well-being and the moderating role of principal transformational leadership, as informed by the broaden-and-build theory of positive emotions and the trait activation theory. We verified this study’s hypotheses based on 768 valid questionnaires collected from Chinese primary and secondary school teachers. The results reveal that teachers’ emotional intelligence can predict their organizational commitment both directly and indirectly through the mediating role of psychological well-being. Additionally, principal transformational leadership amplifies the positive effect of teachers’ emotional intelligence on psychological well-being and, subsequently, organizational commitment. These findings theoretically deepen our understanding of the psychological pathways and the boundary conditions linking teachers’ emotional intelligence to their organizational commitment, while also offering valuable practical implications for building a stable and effective teaching workforce.