This study examined the operation of resources as a mechanism underlying the relationship between career adaptability and career satisfaction. Based on career construction theory and conservation of resources theory, we examined the interactive effects of career adaptability, career satisfaction, person–job fit, and job uncertainty. The results of two-wave data collection from 234 full-time workers revealed that employees with stronger career adaptability were more likely to report career satisfaction. The full mediating effect was found of person–job fit. Specifically, we found that career adaptability enhances person–job fit, which results in greater career satisfaction. Additional analysis revealed that job uncertainty interferes with the mediation model. We identified a new antecedent of career satisfaction (i.e., person–job fit) and revealed the functional mechanism underlying the effect of this antecedent. This study provides novel insights valuable to the field of career management.