This research delves into the complex interconnections among education training, principal supervision, teacher competency, and teacher performance in higher vocational colleges situated in the Western Guangdong region of China. In light of the growing significance placed upon educational quality and outcomes, it becomes imperative to comprehend the intricate dynamics inherent within these variables. Employing a comprehensive mixed-methods framework, encompassing both quantitative surveys and qualitative interviews, the researchers gathered data from a diverse cohort of participants, comprising teachers, principals, and educational administrators. The results of the study demonstrate a noteworthy mediating influence of teacher competency in the association between principal's supervision and teacher performance, as supported by statistical significance. Moreover, this research delves into the examination of the prospective nature of educational training in relation to the development of teacher competence, which subsequently impacts teacher performance through the intermediary function of competence. This study serves as a valuable contribution to the existing body of knowledge by shedding light on the intricate dynamics that exist between education training, principal's supervision, teacher competency, and teacher performance. By focusing specifically on the context of higher vocational colleges in China, this research offers valuable insights into the underlying mechanisms that foster educational excellence within this distinct educational setting.