Aligning with the principles of positive psychology, a critical aspect that has gained prominence in academic territory over the past 2 decades is the concept of well-being. And the recent scholarly articles have underscored the centrality of teachers' psychological well-being (PWB). Given that the well-being and success of teachers are contingent upon their workplace environment, external factors such as the behaviours of the principals wield considerable influence over them. In alignment with this premise, the present investigation sought to scrutinise the structural interplay between principal transformational leadership behaviours (TLB), well-being and success within a cohort of 520 Chinese English as a Foreign Language, who were selected through convenience sampling. After the distribution of three self-report scales among the participants to assess their perceptions of principals' behaviour, PWB and success, structural equation modelling (SEM) was utilised for statistical analysis to evaluate the hypothesised model. The outcomes of the analysis revealed that principal TLB explained 62% of the variance in the participants' success and 57% of the variance in their PWB. The implications of these findings for the extant literature are deliberated upon, leading to recommendations for policymakers and practitioners based on the results.