Adolescents and young adults living with chronic illness experience more complications and challenges when transitioning to adult-oriented care. Despite various interventions to support medication management, goal setting, and collaboration with care teams, AYAs continue to struggle, affecting their health and life outcomes. In this dissertation, I investigated how designing to capture and integrate youths' stories into journey tools can support reflection and empower youth in their chronic illness journeys. I did this work in the context of youth who have undergone kidney transplantation as a focused example of a chronic illness journey. I first examined the experiences of youth transplant patients and their caregivers as they recalibrated to normalcy post-transplant. As a result, I identified five dimensions of their experiences. These dimensions represented the fluctuating nature of patients' and caregivers' experiences post-transplant. Informed by the rich understanding of their experiences, I contributed a conceptual framework that ties together multiple facets of patients' lives and represents the different needs and tensions that may arise throughout various parts of the transplant journey. I then probed further into youth transplant patients' experiences to better understand their transplant journeys. Consequently, I characterized and discovered story categories that youth transplant patients and their caregivers discussed for each of the five dimensions of the framework. Additionally, I explored another essential element of youth's chronic illness journeys, medication management, and provided insights into medication management visuals to help support youth throughout their journey. From this work, I contributed new design insights for capturing youth kidney transplant stories and medication management to inform the design of chronic illness journey tools. Lastly, I explored the impact of My Kidney TREK, a tool designed to capture youth kidney transplant patients' journeys in a real-world setting. Informed by design insights from my previous work, this tool provides youth with a comprehensive view of their kidney transplant journeys. I found that My Kidney TREK positively impacted patients' and caregivers' reflections on their transplant journey, demonstrating the value of incorporating stories within a chronic illness journey tool. Additionally, I discussed the design of the My Kidney TREK and provided recommendations to improve future chronic illness journey tools. Regardless of their health challenges, youth with a chronic illness still have hopes for their futures and aspire to thrive throughout their journey. Capturing and reflecting on their chronic illness stories provides a more holistic picture of their journeys, highlighting barriers that interfere with harmonizing their healthcare and life needs. Ultimately, my work shows how using digital journaling promotes self-efficacy as youth transition towards independence and empowers them to take more control of their lives. This research offers a promising avenue for improving the healthcare journey for youth with a chronic illness. [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.]