After 22 years of public education experience serving students with disabilities and those learning English as a second language while supporting new teachers through the mentorship of veteran instructional staff, the status of U.S. schools continues to decline. The purpose of this qualitative study is to examine the leadership styles and behaviors of schoolteachers in the United States using social media, such as LinkedIn, among diverse ethnic groups under the leadership of principals leading students in grades K-12 under state departments of education. Teachers provided their perceptions that support the sustainability and accountability of high achievement in schools with diverse populations of learners based on their principals' leadership styles and behaviors. Data were collected through structured, in-depth interviews with 15 teachers to find the different characteristic attributes of instructional behaviors for supportive leadership. This research explored school climate and leadership behaviors that increased and supported student achievement in U.S. public, charter, and private schools. The theoretical framework was based on practice. Positive school culture is essential as principals use the most effective leadership styles and behaviors to guide students to high achievement levels while building and sustaining a culture that benefits stakeholders (Cruickshank, 2017). Research suggests that transformational leadership theory supports school culture through leadership styles and behaviors. Burns introduced transformational leadership theory in his 1978 leadership book. This leadership style encourages its followers to increase morality and motivational levels in their workplace environments. This theory also suggests that a transformational school leader develops and implements a culture that ensures increased student learning through positive influence (Siangchokyoo et al., 2020). Transformational leaders allow students' voices to aid in improving existing problems with shared problem-solving strategies with faculty and staff members within their learning community. Thus, teachers describe principals' leadership styles, behaviors, and school climates through structured interviews. This research study illustrated how teachers described school principals' instructional leadership styles and behaviors in state public, charter, and private learning institutions to foster academic achievement among students in schools with similar obstacles in different areas of the U.S. State Department. The overarching research questions were as follows: Q1) How do school principals influence leadership among stakeholders in public and private state department schools in the United States? Q2) What are the perceived school principal leadership behaviors that build instructional excellence within K-12 learning institutions in public, charter, and private state department schools in the United States serving students of diverse backgrounds? Q3) How do school principals develop and implement student achievement among all learners in K-12 learning institutions in public and private state department schools serving students of diverse backgrounds in the United States? [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]