Schrenzinger and Wettstein (2019) define classroom management as the actions a teacher takes to develop a classroom atmosphere where students feel supported, and the teacher facilitates academic success and social-emotional learning. The problem addressed in this research is classroom management in secondary public-school settings continues to be a weakness despite the evidence-based strategies and frequent training made available for teacher implementation in the classroom and should be studied from the point-of-view of principals to gain further insight (Ozen & Yildirim, 2020; Schrenzinger & Wettstein, 2019). A qualitative descriptive case study was used to investigate principal perceptions of teacher personality traits and professional attributes that support effective classroom management (Bloomberg, 2018). Principals participated in an initial survey followed by a one-to-one interview to clarify and expound on the survey responses. The theoretical framework supporting this research is the theory of operant conditioning by B.F. Skinner (Peck, 2013; Schlinger, 2021) and the congruent communication theory of Haim Ginott (Dwek et al., 2017; Yates & Holloman, 2013). The research consisted of 6 Texas high school principals with varying levels of experience, but all had at least 5 years of principal experience. Thematic analysis was used to analyze the principals' responses which resulted in discovering teachers need to possess strong emotional intelligence and work ethic, effective communication, adhere to ethical standards, and develop a learning environment conducive to learning through the development of a highly structured classroom setting. [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.]