The purpose of this study was to determine the effect of principals’ leadership abilities on school performance, both directly and through their schools’ organizational culture. This study adopted a survey design and applied a quantitative approach when analyzing the data. The dependent variable for this research was school performance, an interactive variable was school culture, and the independent variable was school principal leadership. The population for this study was the school principals in charge of the schools/madrasahs under the auspices of Palangka Raya City Education Office, with these ranging from elementary schools to high schools and involving 46,194 people. The study’s sample comprised 350 school principals who had served at least one year to ensure that they had applied leadership methods and established a new school organizational culture during their one year in office. To collect data, this study used survey questionnaires, which were divided into three parts, namely the principal’s managerial style, school organizational culture, and school performance. All the instruments were developed by the researcher with reference to the theories, dimensions, and indicators that have been previously put forward by experts and researchers. Our results show that a principal’s leadership ability can have a significant effect on school performance, but it also influences the organizational culture of the school and improves performance through this channel. However, the direct influence of a principal’s ability on school performance is greater than when it transmits through the school’s organizational culture because a school’s organizational learning also affects school performance.