A circular economy is defined as a socially responsible, policy-driven model of business or enterprise operations that contributes to more sustainable society for both current and future generations. Although the implementation of circularity principles in the economy is a long process, the impact it creates on sustainability is long-term, and its benefits will be felt by all future generations. Therefore, the development of circularity in the European Union’s economy must progress, and more and more organizations should implement it as a good practice. The object of the article is the cooperation of civil sector outsourced services and the country’s military forces in the field of reverse logistics. Using a qualitative research methodology, the article demonstrates the potential for the country’s military forces to support the European Union’s circular economy initiative in the context of sustainability. This includes reducing the consumption of natural resources by increasing the value of the closed-loop supply chain and keeping products suitable for consumption as long as possible. Considering the fact that there is limited information dissemination within the military sector, this research presents one of the few opportunities to examine the integration of civilian and military sector efforts for sustainable development from a practical and scientific perspective. The conducted research demonstrates that the closed-loop supply chain and the military’s reverse logistics processes take place but are not fully integrated into one whole. They lack a unified whole directed towards a common goal when reverse logistics activities are correlated to closed-loop supply chain and national circular economy goals, as well as ensuring sustainability. Outsourced services are available and used in the military, in many cases even for reverse logistics activities (repair, storage, transportation, modernization, etc.). This research made it possible to prepare a conceptual model for the organization of the military’s reverse logistics using outsourced services, thereby ensuring the creation of a sustainable supply chain.