The key challenges in sustainable elite sports concern young athletes´ holistic development. Consequently, preparation for dual careers has been recommended to enhance athletes’ well-being and equip them for life after sports. The aim of this study was to examine the developmental associations between self-esteem and career adaptability among adolescent athletes across the high school years and investigate the role of gender in these developmental trajectories. A total of 391 student-athletes were followed up four times from the beginning of high school (T1) to its end (T4) using the Dual Career Form of the Career Adapt-Abilities Scale and the Self-Esteem Questionnaire. The results indicated that individual differences in student-athletes’ self-esteem and career adaptability were relatively stable across the high school years and were thus modeled via the between-persons factors capturing differences between individuals across time. The results further showed that the overall levels of self-esteem and career adaptability were positively associated. Males showed higher overall levels of career adaptability and self-esteem than females. This study suggests that it is important to facilitate youth athletes’ self-regulation resources by involving them in vocational developmental tasks. Further, gender differences should be considered when supporting student-athletes’ development.