Enhancing the career adaptability of university students is a practical necessity for addressing the challenge of student employment. This study explores the relationship between basic psychological needs satisfaction and career adaptability among university students based on Basic Psychological Need Theory and Social Cognitive Career Theory and constructs a corresponding chain mediation model. A survey was conducted among 635 university students from six provinces across China. The results indicate the following findings: (1) grit partially mediates the relationship between basic psychological needs satisfaction and career adaptability among university students; (2) career decision-making self-efficacy also partially mediates this relationship; and (3) grit and career decision-making self-efficacy serve as chain mediators in the relationship between basic psychological needs satisfaction and career adaptability. This study provides empirical support and significant guidance for enhancing the career adaptability development of university students.