Abstract Individuals with high career adaptability tend to navigate career transitions more smoothly. To address the challenges associated with pre-service teachers transitioning from students to teachers, it is essential to explore the development of their career adaptability. This study aims to investigate the growth of four dimensions of career adaptability in pre-service teachers—career concern, career control, career curiosity, and career confidence—over a semester, as well as how internship experiences and emotion regulation strategies (specifically cognitive reappraisal and expressive suppression) influence this growth. Three surveys were conducted over the semester, involving 779, 683, and 448 pre-service teachers, respectively, who completed questionnaires assessing career adaptability three times and emotion regulation strategies once. The results of the latent growth model showed significant increases in career concern, control, and curiosity over time, whereas career confidence exhibited a gradual decline. Both internship experiences and emotion regulation strategies predicted different aspects of career adaptability. The findings provide empirical evidence for optimizing teacher education programs, ultimately aiming to enhance the overall career adaptability of pre-service teachers.