This study was designed to investigate the relationships among primary school principal teaching leadership, the job involvement of teachers, and instructional innovation. This study aimed to investigate the current status and interrelationships among primary school principal teaching leadership, the job involvement of teachers, and instructional innovation. A literature analysis and a questionnaire survey were used as the primary research methods in this study. A total of 540 questionnaires pertaining to the above three variables were administered to a sample of teachers from selected primary schools, and there were 352 returned questionnaires with valid responses. The researcher conducted descriptive statistics, the product-moment correlation coefficient, and structural equation modelling (SEM) for data analysis. Based on the analysis of the results, teachers of primary schools have a high degree of awareness of the current status of the principal’s teaching leadership, the job involvement of teachers, and instructional innovation. The teaching leadership of the principal influences instructional innovation through the job involvement of teachers, and the job involvement of teachers has an intermediary effect. Therefore, this study had the following suggestions: 1) set up a teaching leading team and a leadership school development curriculum; 2) establish a professional mutual assistance community to improve the enthusiasm of teachers; 3) activate the praise method of competition and encourage teachers and students to participate in the competition; 4) strengthen teaching leadership practice and enrich the energy of school development; and 5) promote the job involvement of teachers and intermediary teaching innovation practices.