This study examines how supply-chain circularity (SCC) translates into firm performance in Nigeria's synthetic-hair industry by testing a mediated pathway from SCC to resource-utilization efficiency (RUE) and onward to operational efficiency (OE). Motivated by the need to move beyond advocacy toward mechanism-focused evidence in developing-country contexts, we implemented a quantitative design comprising a structured questionnaire administered to industry personnel in Lagos (managers, supervisors, and production staff; N = 138) and a complementary public-perception survey of consumers (N = 382). Using Partial Least Squares Structural Equation Modeling (PLS-SEM) for the firm-side data and descriptive analysis for the consumer data, the results indicate that SCC does not exert a significant direct effect on OE; instead, SCC significantly enhances RUE, which in turn strongly improves OE, thereby validating a mediated SCC→RUE→OE mechanism consistent with the Natural Resource-Based View. Moreover, consumer evidence suggests that sustainability is salient, yet purchase decisions hinge on credible quality assurances, price fairness, hygiene and trust, alongside openness to disposal guidance. Collectively, these findings position resource-utilization efficiency as the transmission channel through which circular capabilities convert environmental intent into operational advantage. They also underscore that such operational gains are most likely to be realized in the market when firms pair efficiency improvements with visible quality signals and clear end-of-life instructions.Implications: The study shows that circular practices improve operations indirectly by improving resource-use efficiency, not through a direct operational effect (SCC → RUE → OE). Managers should therefore focus on strengthening resource-efficiency routines, translate those gains into market value through visible quality assurance and disciplined pricing, provide clear end-of-life guidance, and rely on supportive policies that incentivize waste reduction and better input management.