Collaboration between teachers and academics can have a sustainable impact on teachers' professional development. Accordingly, the aim of the study was to investigate the effect of the academic counseling model (ACM) based on academic-teacher collaboration on the pedagogical content knowledge (PCK) of in-service teachers. The ACM consists of five steps: diagnosis, training, action, gradually decreasing, and evaluation. The seven volunteer science teachers in different seniority levels participated in the research from three secondary schools (urban, suburban, and private schools). A total of six academics, four of whom were in the counseling team and two in the support team, took part as the academic team. We collected the data with an observation form developed according to the three components of PCK. The application period was about 23 weeks. We found statistical differences in all stages of ACM, except for gradually decreasing and evaluation, according to the classroom practices of the participant teachers. Consequently, we determined that ACM significantly improved science teachers' professional skills on PCK. In this study, we focused on teachers' professional development, which is a sub-variable of the school variable of ACM. In future research, more comprehensive studies focusing on other sub-components will be useful to reveal the impact of the model.