This dissertation research delved into the lived experiences of primary care nurses who have completed a one-year formal nursing fellowship program. The purpose of this qualitative phenomenological study was to better understand the lived experiences of primary care nurses in leadership or practice after completing a one-year fellowship program with a curriculum focusing on leadership and nursing competency development. Semi-structured interviews were completed with seven participants. Data analysis yielded four distinct themes: Career Development and Trajectory, Support and Leadership, Challenges and Frustrations, and Professional Growth and Confidence. The findings resulted in four key insights about nursing leadership and career growth, informing the evidence-based proposed solution of an Adaptive Primary Care Nursing Fellowship Program. This program prioritizes the enhancement of educational opportunities and leadership training, with an emphasis on leadership, problem-solving, ethics, and preventative care services. The anticipated outcome of the fellowship program is to foster systemic changes and innovation within the healthcare sector, thereby improving patient outcomes, overall performance, and job satisfaction among nurses. [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.]