In response to the call for new studies on the so-called fifth stage of intellectual capital (IC), this study has two main goals. First, it aims to explore how IC affects sustainability in a triple bottom line perspective, namely, the joint and synergic achievement of economic, social, and environmental results in the waste management sector. Second, this study aims to understand how (private vs. public) ownership affects the IC–sustainability relationship. After carrying out a qualitative study on an Italian waste management firm with a strong sustainability orientation and a circular economy business model, we find first, that, IC contributes to the triple bottom line performance to the extent that the commitment to sustainability is integrated into the full range of governance and managerial processes, including those involving IC. Second, we find that stakeholders’ proactive involvement in IC processes is crucial to develop, exploit, and then replicate and scale sustainable business models. Third, we conclude that public ownership is more suitable than private ownership for directing IC processes toward sustainable performance, owing to lower pressure on profits and dividends, willingness to invest with delayed returns, and stronger relationships with the community.
