Hearney commanded at the squadron, air group, and air wing level. During Desert Shield and Desert Storm he served as Deputy Commander, I MEF. His staff tours included Deputy Director, J-3, U.S. European Command as well as Deputy Chiefs of Staff for Requirements and Programs, and Aviation at Headquarters Marine Corps, Washington, D.C. General Hearney was advanced to general and assumed the position of assistant commandant on July 15, 1994.