In the volatile era of the 21^st century marked by globalization and technological advancements, the continuous search for an effective school leader rests on meeting the demands of multicultural academic organizations particularly in terms of building a positive school climate conducive for learning.  Despite the proliferation of educational leadership models, the changing times call for further introspection of the nature and effects of school leadership especially in a culturally diverse setting.    Specifically, this study is to assess the perceived level of cultural intelligence and leadership styles of school leaders in national secondary schools in Kuala Lumpur, as well as their schools’ level of organizational health.  In addition, this research seeks to analyze the relationship between cultural intelligence, leadership styles, and organizational health.  Following a sequential explanatory mixed methods design, a survey questionnaire was administered to 476 school leaders in Kuala Lumpur, and this was followed by interviews with eight school leaders, nine teachers, and observational field notes from four national secondary schools in Kuala Lumpur.  The survey questionnaire used for this study was adapted from the Cultural Intelligence Scale (CQS), Multi-factor Leadership Questionnaire (MLQ 5x-Short), and Organizational Health Inventory for Secondary Schools (OHI-S).  The quantitative data was analyzed using SPSS v22 for descriptive statistics rendering mean scores and standard deviation.  Smart PLS-SEM 3 was also used for model evaluation and hypothesis testing.   For the qualitative data, Atlas.ti v8 was utilized for thematic analysis.  The quantitative findings showed that the school leaders have high levels of cultural intelligence and transformational leadership with mean scores greater than 3.66, moderate level of transactional leadership with a mean score between 2.34 to 3.66, and low level of laissez-faire leadership with a mean score lower than 2.34. The school leaders also rated their organizational health with a high level with a mean score greater than 3.66.  Moreover, the interview responses and observational field notes yielded codes and themes that explained ways school leaders use their cultural intelligence and employ transformational or transactional leadership attributes, as well as the state of their organizational health that indicated a healthy school climate.  While significant effects exist between the constructs of this study, the results of the structural equation modelling established the mediating role of transformational and transactional leadership on the relationship between cultural intelligence and organizational health.  From the integration of the quantitative and qualitative findings, this dissertation arrives at a framework of understanding school leadership in a globalized, multi-cultural 21^st century learning environment.  Aside from extending the understanding of school leadership in a multicultural setting, the findings of this study may serve as a guide in developing programs and policies to strengthen leadership capabilities through cultural intelligence modules, as well as sustain or improve the organizational health of schools through effective leadership and adequate financial assistance.