The U.S. military is entrusted with stewardship of a diversity of natural resources on over 30 million acres throughout the United States. Beginning in 1960 with passage of the Sikes Act, the military established natural resources management programs based on multiple use and sustained yield. Protection of single species regulated under the Endangered Species Act grew more important in the 1970s and 1980s. In the early 1990s, military policy makers and field personnel recognized a need to adopt a new management approach. Ecosystem management was adopted as a process for making, implementing, and evaluating decisions affecting the management of natural resources. This approach was implemented with new policy directives, partnering with government and nongovernment agencies, and an emphasis on biodiversity conservation. The ecosystem approach ensures the sustainability of natural resources and supports the Army’s triple bottom line: mission, environment, and community. This paper traces the history of conservation stewardship in the military and the evolution of ecosystem management on military lands. The approach could serve as the basis of a nascent ecosystem services methodology.