This study describes the learning and development experiences of teacher education students after taking an introductory course on adolescent psychology. The instructor adopted the developmental instruction model (DIM) (Knefelkamp, 1998) in this study and facilitated students learn through experiential learning. Fifteen students (aged between 20 and 28, with an average of 23.25) submitted a report and a research paper during the course and were invited for an in-depth interview after the course ended. Each student provided three sets of data (a brief paper, a research report, and an interview), and the instructor and research assistant recorded observation/reflection notes which were all analyzed with phenomenological qualitative method. Six themes emerge: (1) improved self-understanding including review of characteristics of their adolescence and how their adolescence makes who they are; (2) better understanding of modern youngsters including characteristics of adolescents in Taiwan and other countries and the challenges they encounter; (3) understanding of impacts of environmental factors (family, campus life, society and culture) on teenagers such as how changes in environment affect them; (4) acquisition of counseling techniques for adolescents; (5) experiencing the effectiveness of experiential learning; and (6) recognition of the practicality of DIM. The findings of this study served as the foundation for teacher education students to go deeper into the world of adolescent psychology, and for designing and selection of pedagogical methods for psychology courses. Findings supported that this course could enhance teacher education students' understanding of themselves and adolescents. It also could solidify their teaching and counseling skills for youngsters.