Although the number of principal preparation programs (PPPs) has continued to grow, researchers have voiced concerns about the effectiveness of these licensing programs, particularly given the importance of a principal in student achievement and teacher retention. The purposes of this study were to evaluate the perceptions of graduates of the Aspiring Assistant Principal Network (AAPN) program about their preservice content and activities and to determine the program experiences that supported their leadership identity development. The research questions were: (1) How do AAPN program graduates perceive the relevance of program activities and resources for educational leaders? and (2) What AAPN program experiences supported graduates' leadership identity development? This convergent mixed methods study was conducted with graduates of the first two cohorts of an innovative, online PPP at a 4-year public university in the southeastern United States. From Cohorts 1 (n = 59) and 2 (n = 72), 131 graduates completed an alumni survey 5 months after graduation. Additionally, 26 program graduates completed a leadership identity survey, either 1 or 2 years post-graduation, consisting of nine building-level administrators (i.e., principals, assistant principals), five building-level leaders (e.g., instructional coach, teacher-leader), three district-level leaders (e.g., Director of Communications), and nine educators (e.g., classroom teachers, counselors). Data analysis consisted of descriptive statistics and thematic analysis. Findings included that 87.8% of alumni felt prepared for a role in educational leadership, and that coursework (65.4%) and interactive feedback (100%) were the most relevant program activities and resources. Self-reflection and effective mentor principals were found to be significant aspects of leadership identity development. Implications for practice include continuing extensive synchronous feedback and interactions, self-reflection to support professional learning, and incorporating the leadership identity development model as a program framework. Implications for research include developing an ongoing survey to drive AAPN program improvement and provide networking opportunities and to include interviews in follow-up studies. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]