This study explores the relationship between university students' participation in extracurricular activities (ECAs) and employability from a sustainable development perspective, based on Kolb's Experiential Learning Theory. A survey of 448 undergraduates from a university in Chongqing, China, examined correlations between ECAs and four dimensions of employability (subject understanding, skills, self-efficacy, and metacognition). Results show that higher participation in ECAs is associated with improved subject understanding, self-efficacy, and metacognition. First-year students had higher ECA participation and advantages in certain employability dimensions. Disciplinary differences influenced participation but not perceived employability. Findings suggest that continuous participation in ECAs can enhance cognitive and non-cognitive abilities, providing empirical support for higher education institutions to design inclusive and theory-oriented student development strategies aligned with Sustainable Development Goal 4 (SDG 4).