Charter schools have carved a niche in public education, but despite an increased number of studies in charter schools in recent years, the research in charter school leadership is not adequate. School Leadership is critical for school success; it is the second most significant factor for influencing student academic achievement after classroom teaching and curricula (Robinson et al., 2008; Day et al., 2008, Leithwood, 2006; Marzano, 2001). The purpose of this correlational study was to explore the Illinois charter school principals' characteristics and leadership qualities (leadership style, leadership outcome, and cultural intelligence) and their relationships with the school learning environment as well as school and student outcomes. Like Vickers's (2014) study, charter school principals included in this study are more likely to be female, younger, nonwhite, and have less teaching experience than both Illinois and national traditional public school (TPS) principals. The study discovered a statistically significant correlation between gender and transformational leadership, which could explain 16.2% of the variance in transformational scores. The bivariate correlational analysis between leadership qualities revealed that cultural intelligence has a positive relationship with all leadership styles and outcomes except laissez-faire leadership. The participants' transformational leadership style, Extra-effort and Effectiveness leadership outcomes (as measured by MLQ), and Cultural Intelligence (as measured by CQS) have a positive relationship with the learning environment and 5Essentials. The correlation between the leadership qualities and the school outcomes only revealed a positive correlation between the teacher retention and MLQ Effectiveness leadership outcome. This study confirmed that there is a strong relationship between cultural intelligence, transformational leadership, and leadership outcomes as measured both by MLQ and by their associations with school learning environment measured by 5Essentials. The school principals are better off utilizing the transformational leadership style and cultural intelligence leadership qualities to become effective and sustainable instructional leaders. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]