The U.S. military conducts a full spectrum of contingency operations in which it provides humanitarian assistance, logistical support, peacekeeping stability functions, and reconstruction activities. It is becoming increasingly important to incorporate the concept of “sustainability” into these operations. Making contingency operations more sustainable will provide force multiplier aspects that increase operational efficiencies and reduce logistical burdens and costs. The military requires enormous energy resources to maintain its mission readiness, which contributes greatly to logistical burdens and costs. A wide range of sustainability considerations relate to the cross-functional use of energy in contingency operations, from the interface with a host nation’s infrastructure; temporary construction practices; fuel convoys; cascading material use; the handling and treatment of waste, water, and hazardous materials; logistics footprint, etc. This paper describes military issues that will affect deployed base mission requirements and future investment policies. It also describes the ongoing process to develop an Army vision for sustainable contingency operations. This vision will consider the integration of cross-functional energy uses and establish sustainable operational requirements and investment policies. These insights are also applicable to many international humanitarian situations.