This study aims to explore the generational differences in professional identity formation (PIF) among medical students and physicians in Taiwan, focusing on the challenges to medical professionalism posed by technological advancements, societal changes, and diverse values. The study integrates Kegan's Constructive Development Theory, the Community of Practice (CoP) framework, Self-Determination Theory (SDT), and Social Learning Theory (SLT). Using a mixed-methods approach, it combines quantitative survey analysis with qualitative insights from in-depth interviews to systematically examine the key factors influencing professional identity formation. The research participants include Taiwanese medical students, residents, and attending physicians from different generations. The study investigates how structural factors—such as digital technology, sociocultural contexts, and educational and training models—shape generational differences. Through the comprehensive analysis of quantitative and qualitative data, the research aims to uncover commonalities and differences in professional values and core principles across generations. It seeks to deepen theoretical understanding of professional identity formation in medicine, provide evidence-based insights to address future challenges, and propose recommendations for medical education reform, ultimately contributing to the development of a higher-quality medical education system in Taiwan.