The focus of this study was to examine the impact of professional development on the leadership practices of Head Start program directors in the Southwest United States. The research sought to understand how professional development influences the leadership practices of these directors and aimed to provide practical insights into leadership in the field of early childhood education (ECE) and professional development systems. The study used a qualitative descriptive case study method to understand how professional development affects early childhood education leadership practices. The research was grounded in the theoretical of The Whole Leadership and Continuous Professional Development frameworks. Questionnaires, semi-structured interviews, and a focus group gather data from twenty-one participants. The analysis followed Braun and Clarke's six-step thematic analysis, identifying three themes related to the research questions about the influence of professional development on administrative and pedagogical leadership practices. The findings highlight the importance of specific professional development experiences in shaping leadership practices in early childhood education. It enriches the existing literature on ECE leadership and offers practical implications for developing professional curricula and activities for ECE leaders, especially Head Start program directors. The study offers valuable insights into effective leadership development strategies and provides relevant information for enhancing leadership practices in early childhood education. [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.]