The purpose of this phenomenological study was to explore the experiences of Early College High School (ECHS) adjunct instructors teaching dual enrollment courses in a southern region school district. Through interviews with ten ECHS adjunct instructors, the researcher examined the factors contributing to their success, their professional development needs, and the challenges they faced in teaching dual enrollment courses. Findings of the study were that ECHS adjunct instructors succeed when they provide strong student support, maintain open communication, demonstrate flexibility, and actively engage students. The study has highlighted the need for comprehensive training in learning management systems, curriculum design, and differentiated instruction. Additionally, collaborative learning environments, such as professional learning communities (PLCs) and peer observations, were identified as essential for enhancing teaching practices. Key challenges identified in the findings included balancing the dual expectations of high school and college, managing student readiness for college-level work, and limited access to tailored professional development. Findings imply the need for a structured professional development framework that promotes collaboration between community colleges and ECHS administration, focusing on continuous growth, tailored training, and supportive networks for ECHS adjunct instructors. [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.]