The purpose of this study was to investigate the perceived effects of "Principal-Leadership" behaviors, and if they were effective in positively influencing school performance and student success in Residential Schools for Secondary Level Deaf Students. Specifically, it investigated the degree to which the Principal-Leader's measurable behaviors--as assessed by the Vanderbilt Assessment of Leadership in Education instrument--followed the conceptual framework of learning-centered leadership, and the degree to which the Principal-Leaders demonstrated Transformational Leadership behaviors. This parallel mixed-methods study investigated three research questions. Research Question #01: To what extent will each of the VAL-ED instrument's six Core Components--(1) "High Standards for Student Learning"; (2) "Rigorous Curriculum"; (3) "Quality Instruction"; (4) "Culture of Learning and Professional Behavior"; (5) "Connections to External Communities"; and (6) "Performance Accountability"--and the six Key Processes (1) "Planning"; (2) "Implementing"; (3) "Supporting"; (4) "Advocating"; (5) "Communicating"; and (6) "Monitoring," show a correlation between Principal-Leadership behaviors and student success? Research Question #02: Based on the VAL ED's 36 possible combinations of six Core Components and six Key Processes, will "Principal-Leaders" with a higher percentage of "Proficiency" rating scores be associated with differential levels of student success? And Research Question #03: Transformational leadership is defined as developing relationships with individuals to increase motivation to perform beyond expectations. In what ways has the "Principal-Leader" demonstrated the behaviorally observed application of transformational leadership? Quantitative data were collected from the results of the Vanderbilt Assessment Leadership in Education survey, an instrument that provides a summary of the Principal-Leaders', Teachers' and Superintendents' perceptions of their Principal-Leader's effectiveness on learning-centered leadership behaviors that have been found to correlate with student success (Murphy, Goldring, Cravens, Elliott, & Porter, 2007). Qualitative data were collected from Videophone interviews, participant demographic questionnaires, and student archival data for analysis. The findings from the VAL-ED assessment instrument resulted in the emergence of three groups of Principal-Leaders and Principals, who scored "Proficient," "Basic," and "Below Basic." For Research Question #01, a negative, statistically significant correlation was found for one of the VAL-ED's six Core Components, "Culture of Learning and Professional Behavior," and "Total Sum of Student Attendance Rates." No statistical significance was found in the correlation between the other Core Components and "Total Sum of Student Attendance Rates," "Total Sum of Student Graduation Rates" and "Total Percentage of College Enrollment Rates." A negative, statistically significant correlation was found for one of the VAL-ED's six Key Processes, "Advocating," and "Total Sum of Student Attendance Rates." Also, no statistical significance was found in the correlation between the other Key Processes, and "Total Sum of Student Attendance Rates," "Total Sum of Student Graduation Rates "and "Total Percentage of College Enrollment Rates." For Research Question #02, no statistical significance was found in the correlation between and among the three "Proficient" Principal-Leaders and "Total Sum of Student Attendance Rates," "Total Sum of Student Graduation Rates" and "Total Percentage of College Enrollment Rates." There were inconsistencies within the data which may have contributed to these results. However, for Research Question #03, the 45 participants who were interviewed supported the results of the VAL-ED assessment instrument, including whether the Principal-Leaders displayed Transformational Leadership behaviors. Principal-Leaders who scored "Proficient" on the VAL-ED assessment instrument had a higher proportion of Transformational Leadership behaviors in comparison to the Principals who scored "Basic" or " Below Basic." In conclusion, Principal-Leaders who were "Proficient" were effective in demonstrating "instructional leadership" and "transformational leadership" behaviors. [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.]