Lighting retrofits that couple efficient LEDs with smart controls can deliver exceptional energy and cost savings. Yet because of integration challenges,few buildings realize their full potential. At Department of Defense (DoD) installations in particular, many buildings still operate inefficient legacylighting systems with basic or limited controls. Adding smart controls to aging lighting systems is rarely justified. And adding third-party smart controls toan LED retrofit project can create new problems with compatibility, design, and installation. State-of-the-art lighting systems overcome these challengesusing fixtures with fully-integrated sensors and wireless controls. These architectures pose new questions about cybersecurity, resilience, and practicality. Aspart of a multi-year validation effort, a fully-integrated wireless LED control system was deployed at three DoD facilities including a gymnasium, supplywarehouse, and aircraft hangar, covering a total floor area of about 200,000 ft² (18,600 m²). The validation examined energy and cost performance,user acceptance, cybersecurity, and other practical considerations. This paper shares preliminary findings and lessons learned from a multi-year fieldmonitoring effort. Results suggest that smart connected lighting systems could play a significant role in providing DoD buildings with more light and lessenergy.