This study aimed to describe the implementation of leadership styles of High-Achieving School Principals in teacher professionalism. This research was conducted using a qualitative method and a human instrument. The participants consisted of 1 school principal, 4 deputy principals, and 2 teachers. The data were collected using in-depth interviews, observation, and documentation. The obtained data were analyzed using data condensation, display, and verification. The results found that the leadership style of high achieving school principals did not only comply with one leadership style. Relationship-oriented, participatory, transactional, and transformative leadership styles were mostly applied in collaboration. Such collaborative leadership style became a strategic approach in supporting teacher professionalism. Of the four leadership styles, transformative style had been the most dominant style as the principal’s vision gave a positive energy to the teachers in developing their competence.
Keywords: leadership, style, principal, teacher, professionalism;