Empirical research has suggested that professional learning communities (PLCs) and employee engagement have a positive impact on the school community, school culture, and academic achievement. Further research has postulated that school leadership is one of the most important ingredients in the success of schools. But do school leaders have any impact on the effective implementation of PLC and employee engagement? The purpose of this study was to determine the impact of school leadership on the effective implementation of PLCs and employee engagement at the high school level. The study was conducted in a large public school district in the northern part of the Commonwealth of Virginia. The research involved school employees in 24 high schools. Data were obtained from an existing study, the Employee Engagement Survey, and interviews with former school personnel from high schools in the district. The research methodology involved the use of a paired-samples t test and correlation analysis to determine the relationship between the variables. Qualitative data were also obtained from interviews conducted with subject matter experts. Based on the results from the data analysis, statistically significant relationships exist between the variables. Additionally, PLCs implemented effectively do have a positive impact on school culture. However, many of the variables, including leadership and work environment, have less impact on student success in this district. Schools with higher levels of engagement have less impact on students' success. The study concluded that school PLCs can have a positive impact on school culture, but leadership and engagement do not necessarily have a significant impact on student success. [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/en-US/products/dissertations/individuals.shtml.]