This research examined the effect of development programs on changing school principals' leadership styles in public elementary schools within the Division of Rizal for the 2024-2025 school year. It also tested how leadership changes impacted the overall performance of schools. This study used a descriptive quantitative research design using a survey method and a questionnaire. The subjects were 20 principals and 200 educators. The research showed that most principals were 41 years and above, with an equal mix of male and female subjects. Moreover, most principals possessed at least seven years of experience and were either pursuing or had completed doctoral degrees. The study assessed the impact of development programs on leadership behavior including idealized influence, inspirational motivation, intellectual stimulation, and individualized consideration. All indicators demonstrated a "High Effect" on leadership strategies, with mean values between 3.02 and 3.16, yielding an overall mean of 3.11. This suggests that the development programs had a substantial positive impact on transforming the leadership styles of the school principals. Furthermore, the study found a significant difference between the transformation of leadership styles and the subsequent improvement in school performance. There was also a moderate positive correlation between the effect of development programs on leadership styles and the sex of the principals, indicating gender-based differences in leadership transformation. The principals' age, years of service, or educational level did not exhibit any significant correlation with the change in leadership. The research indicates that professional development programs for school administrators significantly enhance their leadership capabilities, which has a positive effect on the performance of public elementary schools. The study illustrates the critical nature of educational leaders' pursuit of continuous professional development to enhance academic performance.