The United States has undergone a revamping of education standards in an effort to systematize rigorous learning standards across the country and prepare students to be college- and career-ready. In addition, new accountability requirements have been put in place to determine the effectiveness of the school leader. Certainly, educational reforms and policy changes are not new to the principalship. Principal leadership plays a significant role in the academic achievement of students and in the overall success of schools. This qualitative study examines the effective leadership practices of four urban high school principals. Two principals are leading schools labeled "Good Standing" and two principals are leading schools labeled "Persistently Struggling" by New York State Education Department. Interviews with the four principals and teachers in their buildings, observations, and document reviews were used to collect data on enacted leadership practices by the building principals. This data was then sorted into a core set of effective leadership practices developed by Leithwood and Riehl (setting direction, developing people, redesigning the organization, and improving the instructional program), which served as the conceptual framework and further assisted in the data analysis for this study. As a result of conducting interviews, observations and document reviews with the case study principals, the researcher was able to determine that principals in both accountability designations exhibited all four core practices. The study supports Leithwood's claim that the four core practices are necessary but not sufficient. While a principal can exhibit evidence of all the core practices of leadership associated with leading an effective school, if district policies create challenges outside of the principal's control, the core practices are not sufficient. [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.]