Background <p>Competitive aerobic gymnastics is a high-pressure, judged aesthetic sport that requires sustained training and stable psychological resources. While motivation, flow, and psychological resilience have each been examined in sport psychology, little is known about how these constructs co-develop across an athlete’s career, particularly among late-specializing elites.</p> Methods <p>We conducted a repeated-interview, life-story single-case study of a male aerobic gymnastics world champion who began specialized training later than typical elite pathways. Data were collected through six retrospective semi-structured interviews over eight months, supplemented by relevant archival materials. We used an inductive thematic approach, organized by career phases, to trace within-case developmental patterns.</p> Results <p>The narrative indicated a four-phase trajectory: initial exploration, competitive breakthrough, peak integration, and educational transformation. Across phases, motivational regulation progressively internalized toward more autonomous forms; flow was described as shifting from early or occasional episodes to more accessible and repeatable flow-like states; and resilience developed from basic coping to an integrated repertoire of attentional control, emotion regulation, and meaning-making.</p> Conclusions <p>This single-case narrative is consistent with a provisional, case-based conceptual interpretation in which autonomous motivation, flow, and psychological resilience appeared to develop in mutually related ways across career phases. In this case, autonomous motivation seemed to sustain engagement, resilience-related resources appeared to support flow under evaluative pressure, and recurring flow episodes may have reinforced resilience and motivational internalization. Rather than a general explanatory model, this interpretation is intended as a heuristic framework to guide future multi-case and mixed-method research.</p>