Purpose: This study attempted to determine the influence of exemplary leadership preparation on what principals learn about leadership, their use of effective leadership practices, and how their practices influence school improvement and the school's learning climate. The authors also investigated how the frequency of effective leadership practices related to the strength of district support and the extent of school problems and student poverty. Finally, the authors examined the contribution of exemplary leadership preparation to variations in school improvement progress and school effectiveness climate. Research Design: The study, using survey research conducted in 2005, compared 65 principals who had graduated from one of four selected exemplary leadership preparation programs to a national sample of 111 principals. The authors used structural equation modeling to find the best fit. Findings: Participation in an exemplary leadership preparation program was significantly associated with learning about effective leadership and engaging in these practices, particularly where stronger preparation program and internship quality existed. Frequent use of effective leadership practices was positively associated with school improvement progress and school effectiveness climate. Taken together, exemplary leadership preparation had a positive but mediated influence on variations in school improvement progress and school effectiveness climate; the relationship was even stronger when focusing on preparation program and internship quality measures. Conclusions: Faculty investments in preparation program and internship quality will positively contribute to the leadership knowledge of graduates and their leadership practices and school improvement progress. These results yield significant implications for policy makers, universities, and other providers of leadership preparation. (Contains 5 notes, 4 figures and 4 tables.)