The DAO was established as a subsidiary command of MACV and remained under the command of commander of MACV until the deactivation of MACV on 27 March 1973 at which time command passed to the Commander USSAG/Seventh Air Force at Nakhon Phanom. The DAO was activated on 28 January 1973 with United States Army Major General John E. Murray, formerly MACV director of logistics, as the Defense Attaché and United States Air Force Brigadier General Ralph J. Maglione, formerly the MACV J-1 (Director for Manpower and Personnel), as deputy Defense Attaché.