Prolonged Casualty Care (PCC) is a major US military research focus area. PCC is defined as the need to provide patient care for extended periods when evacuation or mission requirements surpass capabilities and/or capacity. US military experts have called for more data relevant to PCC. In response, we aimed to develop an innovative research model using a tiered system of trauma care in the Western Cape of South Africa as a framework for studying relevant US military trauma care and outcomes in a natural prolonged care environment. The objective of this report is to describe the research model and to illustrate how various components of the model may be helpful to provide data relevant to US military PCC. To develop the model, we used a combination of published data, open access reports, and expert opinion to identify, define, and compare relevant components of the Western Cape trauma system suitable for researching aspects of US military PCC. Several key features of the research model are as follows: In the Western Cape, patients are referred from primary and secondary to tertiary facilities (analogous to escalating capabilities by advancing roles of care in the US military). Western Cape civilian trauma providers' capabilities range from prehospital basic life support to definitive trauma surgical and critical care (comparable to US military Tactical Combat Casualty Care to advanced definitive surgical care). Patterns of injuries (e.g., high rates of penetrating trauma and hemorrhagic shock) and prolonged times from injury to definitive surgical care in the Western Cape system have relevance to the US military. This civilian research model for studying PCC is promising and can inform US military research. Importantly, this model also fills gaps in the South African civilian system and is useful for other prolonged trauma care communities worldwide.