The problem of underachievement seems to exist in school districts across the country, particularly, where there are a significant percentage of students of color and low socio-economic groups. The purpose of this qualitative case study, conducted with an ex post facto approach, was to bring to light the organizational policies and systemic practices that allowed a high poverty, high performing urban school with a large concentration of students of color and low socio-economic students to succeed in a manner that can be translated into effective practices for other schools with the same or similar classification. The traditions of heuristic inquiry and symbolic interactionism assisted in the understanding of the phenomenon of organizational policies and systemic practices. The goal of this study was to illuminate policies and practices in one high performing urban college prep high school and to provide recommendations to improve educational practices in urban high schools. The study constituted a single case with in-depth interviews, surveys and documents collected from students, teachers and administrators. The data were analyzed using the processes of heuristic and symbolic interaction, integrated with procedures for analyzing case study. Themes were identified in the data using thematic and enumerative coding. Findings as depicted through the themes suggest that in order for the students in the school to achieve academic success, the organizational policies and systemic practices within the educational system would need to be re-cultured to reflect the original vision and mission of the school of high expectations and college readiness for all students. Re-culturing requires examining and changing beliefs and assumptions that influence teaching, practices, and interactions with culturally diverse students. Additionally an accountability system was needed to ensure that all students would meet the high expectations of a college prep environment. [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.]