A large, urban school district in the southeastern region of the United States found that leaders supplied by universities lacked skills needed to meet its accountability challenges. Because the school district demands highly effective leaders for its growing schools, an Aspiring Leader Program (ALP) was established to train its future assistant principals. This quantitative, quasi-experimental study investigated the impact of the ALP on 34 assistant principals' and 17 supervising principals' perceptions of leadership behaviors as described on the Kouzes and Posner's Leadership Practices Inventory (LPI). The Mann-Whitney test revealed no significant differences in program and nonprogram assistant principal LPI-self ratings, nor were significant differences found in supervising principal LPI-observer ratings of program and nonprogram assistant principals by the Wilcoxon test. However, an item analysis indicated 3 LPI leadership practices that warranted additional professional learning for all assistant principals. Therefore, a professional learning project to address the 3 LPI practices evolved. In relation to social change, the findings add to the effective leadership literature at both the district and university levels and may contribute to improved school leadership that supports increased student achievement. [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.]