It takes many years for trainees to become physicians-so long that their individual journeys through medical school and residency are seldom systematically studied and thus not well understood. Lack of understanding hinders effective support of future physicians' development across traditional time-bound phases of medical education. The authors initiated a longitudinal qualitative study, tracing a cohort of 6 trainees through the same medical school and 6 different residencies. They asked, how do stability and change characterize the lived experience of trainees through time? From 2010 to 2019, the authors conducted in-depth interviews every 6 to 12 months with 6 trainees, using reflective prompts about formative events and prior interviews. Data were inductively coded and analyzed in an iterative fashion. By scrutinizing data via time-ordered displays of codes, the authors identified 3 patterns of stability and change, particularly related to constructing careers in medicine. The study originated at a private medical school in New York, New York. Patterns in the balance between stability and change were shaped by trainees' career interests. Trainees motivated by stable clinical interests perceived their journey as a "series of stepping-stones." Trainees motivated by evolving clinical interests described disruptive change or "upsets"; however, they were still accommodated by medical education. In contrast, trainees motivated by stable nonclinical (i.e., social science) interests perceived their journey as a "struggle" in residency because of the clinically heavy nature of that phase of training. Based on this descriptive, 9-year study of a small number of trainees, medical education seems to accommodate trainees whose journeys are motivated by clinical interests, even if those clinical interests change through time. Medical education could consider alternatives to time-bound frames of reference and focus on the right time for trainees to integrate clinical and social sciences in medical training. Copyright © 2020 by the Association of American Medical Colleges.