Each adolescent’s career development path is unique and depends on a multitude of cognitive, motivational, and action-oriented factors (Driesel-Lange et al., 2020). If students in school receive individual support, positive effects on their career management skills can be observed (Schindler, 2012; Metheny et al., 2008). In particular, teachers at grammar schools stimulate knowledge-related aspects of career competence, especially by providing informational support (Driesel-Lange et al., 2018). In this four-wave long-term study, we investigated how adolescents (N1-4 = 1,433) develop facets of career competence within one school year. Furthermore, we analysed the effects of perceived teacher support on the development of career competence, controlled for the type of school. Conclusions are drawn both regarding higher education didactics in terms of teachers’ qualifications for career guidance and in terms of the specific contributions of other actors such as external career counsellors. The limitations of the study and implications for further research are discussed.