Occupant comfort is a fundamental consideration during the early stages of vehicle development, with internal spaciousness serving as a key pillar in creating a pleasant in-cabin experience. Among the various factors that contribute to this perception, legroom plays a particularly significant role, especially for rear-seat passengers. This study investigates the relationship between second-row legroom and occupant satisfaction under real-world driving conditions, employing a combination of research, statistical data analysis, and dynamic clinics to assess perceptual comfort. The findings reveal that shin and leg heights are the primary drivers of satisfaction or discomfort, while gender and overall height exhibit only minor influences on perceived comfort. Additionally, the study highlights the importance of other interior dimensions, such as shoulder room, knee clearance, and chair height, in shaping overall comfort since if they were poorly chosen, they would have affected clinic results. The results underscore the need for meticulous ergonomic design and continuous evaluation of vehicle dimensions to meet evolving consumer expectations. Ultimately, this research reinforces the value of occupant-centric design approaches in enhancing comfort and ensuring competitiveness within the automotive industry.