The ultimate goal of career guidance is to help medical students develop a career plan that matches their personal characteristics, allows them to train in their desired subspecialty, and helps them to adapt well to medical practice after graduation. Gachon Medical School has designed a longitudinal career guidance program called GLORI (Gachon Longitudinal Orientation and Career Development), which is based on the outcome of each phase. The program consists of regular courses and portfolio-based career guidance from a mentor professor. In phase 2 (basic medical science), the “Career Seminar” course was developed. This course focuses on self-understanding through a psychological inventory, exploration of postgraduate career paths, and interviews with professors in specialties of interest. In phase 3 (the integration of basic and clinical science), the “Exploring Nonclinical Career Options” course was introduced. This course presents perspectives from doctors who have followed various pioneering career trajectories, including biomedical engineering, medical journalism, writing, public health, health care administration, the pharmaceutical and medical device industries, and other areas. All teaching methods were designed to encourage student participation. The assessment methods are assignment-based, including self-reflective reports and presentations. In addition, a portfolio-based career guidance program is implemented in phases 3 and 4 (clinical clerkship). It is expected that this case study will serve as a practical example for developing comprehensive career guidance programs for medical schools.