Giambastiani's other shore and staff assignments include duties as an enlisted program manager at the Navy Recruiting Command Headquarters, Washington, D.C., in the early days of the all volunteer force; Special Assistant to the Deputy Director for Intelligence, Central Intelligence Agency; and, a fellowship with the Chief of Naval Operations' Strategic Studies Group. As a flag officer, he served as the Deputy Chief of Staff for Resources, Warfare Requirements and Assessments for the Commander, United States Pacific Fleet; Director of Submarine Warfare for the Chief of Naval Operations; Deputy Chief of Naval Operations for Resources, Requirements, and Assessments; and as the Senior Military Assistant to Secretary of Defense Donald H. Rumsfeld. His previous assignment was as NATO's first Supreme Allied Commander Transformation (SACT) and as Combatant Commander of United States Joint Forces Command, where he led the transformation of NATO and U.S. military forces, capabilities and doctrines and the introduction of new technologies, from October 2, 2002 to August 1, 2005.