Extravehicular activity (EVA) space suits are complex, expensive, and difficult to operate and manage. However, EVA is all but required for any human spaceflight operation in orbit or beyond. Final Frontier Design (FFD) has developed and is currently in beta testing of a commercially focused and complete EVA space suit system. This article presents the research and development, testing, and preliminary validation of FFD's EVA space suit enclosure (ESSE) systems, including the liquid cooling garment, pressure garment, bearings, hatch, outer garment, life support system, interfaces, support equipment, and test procedures. The ESSE leverages a decade of work with National Aeronautics and Space Administration and a career of engineering with Zvezda. FFD has developed ground support equipment for laboratory testing and is partnering with Integrated Spaceflight Services to create an immersive test protocol for validation of the systems including a 2 degree gravity offset system. The introduction of a complete commercial EVA system is unique and unprecedented. Although multiple companies have developed intravehicular activity space suits alone, the EVA suit system is massively more complex and traditionally has been assembled using multiple contractors. FFD aims to offer a complete system in-house with ESSE.