This study is a cross-national research in school leadership behaviors. Research subjects in this study include primary and secondary school teachers in Taiwan and northeastern Japan. By referring to "School leadership of the future," this study summarized that school leadership is working toward a team approach to instruction leadership, compound leadership, and diverse leadership. By referring to relevant literature, the researcher also determined pertinent criterion variables, including school effectiveness, teachers' job performance, and teachers' organizational commitment. The results obtained through collecting questionnaire copies and performing statistical analyses are as shown below. Firstly, in terms of the same leadership behavior's contribution to school effectiveness, the two countries revealed some differences. A team approach to instructional leadership is conducive to students' performance in Taiwan and teachers' professionalism in Japan. The two countries also showed differences in different leadership styles' effects in facilitating teachers' commitment. School principals in Taiwan should employ structure and symbol-oriented leadership; whereas, school principals in Japan should employ a team approach to instructional leadership. As indicated by these results, Japan has a stronger team approach to leadership characteristic in comparison to Taiwan. As Japanese culture values team honor, employing a team approach to leadership could facilitate teachers' professionalism and commitment. Due to Taiwanese society's diverse cultures and difficulty in reaching a consensus, setting a clear goal and employing structure and symbol-oriented leadership with an established paradigm or a heroic story may better facilitate teachers' commitment.