As state-funded Pre-K programs in elementary schools continue to grow, elementary principals are increasingly responsible for supporting, supervising, and leading these programs. Therefore, examining elementary principals' early childhood leadership competencies and the factors influencing them may help understand and improve their experiences as early childhood education (ECE) leaders. This explanatory sequential mixed methods study examined the ECE leadership of Tennessee public elementary school principals in two phases. In the quantitative phase, statewide surveys were used to collect data from 67 principals. The survey comprised 51 items assessing nine ECE leadership competencies, synthesized from statements of leading ECE and elementary education organizations. The survey's face and content validity were established, and its construct validity was confirmed through exploratory factor analysis (EFA). Items within each subscale were highly correlated, with coefficients ranging from 0.6 to 0.9. Besides, reliability was assessed using Cronbach's [alpha], which ranged from 0.815 to 0.939. The quantitative findings revealed that public elementary principals may lack ECE backgrounds. Moreover, most public elementary principals were responsible for state-funded Pre-K programs, but their responsibilities differed widely. Furthermore, public elementary principals may need varying levels of support and development in ECE leadership competencies. The inferential analysis found that receiving ECE content or experience during principal training may not significantly influence their perceived need for these competencies. However, receiving professional development opportunities focused on leading ECE programs may impact certain aspects of their perceived need. In the qualitative phase, semi-structured interviews were conducted with six participants from the first phase. The qualitative findings identified two themes. The first theme consisted of factors that support ECE leadership competencies and experiences. The second theme included factors needed to enhance principals' ECE leadership competencies and experiences. Both quantitative and qualitative results were integrated to explain the quantitative results. The study implications, limitations, and future research areas were then discussed. This study adds to the ongoing efforts to bridge the gap between ECE and elementary education. It highlights the significance of supporting elementary principals in becoming competent ECE leaders who can enhance the quality of state-funded Pre-K programs and sustain their positive impacts through the following grades. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]