Christopher Mayer is the Director of Armed Contingency Contractor Policy and Programs for the US Department of Defense (DoD), responsible for policy and Department-level oversight of private security contractors (PSCs). He is DoD Program Manager for PSC standards, advises Combatant Commands on matters regarding contracted security, and is a US government technical advisor to the International Code of Conduct for PSCs. His portfolio includes human rights and anti-human trafficking policy in US contingency contracting.

Prior to his retirement in 2009 as Colonel, he served in the Office of the Secretary of Defense for Policy promoting integrated approaches for post-conflict or disaster relief and recovery and represented the US government in drafting the Montreux Document.

Previous assignments included Chief of Civil-Military Coordination to the UN Mission in Liberia; Chief of Staff for the Defense Reconstruction Support Office; Chief of Staff, Iraq Program Management Office, where Chris Mayer established an operations center to centrally manage PSC support of the reconstruction effort; and leadership and staff assignments in various Armor and Cavalry units.