Command Sergeant Major Gaines joined the Army as a Subsistence Supply Specialist on the delayed entry program. He attended Basic Training at Fort Dix, New Jersey, and subsequently to Fort Lee for Advanced Individual Training. After AIT, he was assigned to several units as a Subsistence Supply specialist which include the 227^th General Supply company, fort Campbell; Headquarters, Alpha Company 3^rd Forward Support Battalion, Aschaffenburg, Germany; Materiel Management Center, Division Support Command, 5^th Division, fort Polk, where he served as the Class One Noncommissioned Officer in Charge (NCOIC); 40^th supply and Service Company; 80^th Area Support Group as the NCOIC Troop Issue Subsistence Activity and the Supply and Services NCOIC; 710^th Main Support Battalion, Fort Drum; Alpha Company, 123^rd Main Support Battalion, Dexhiem, Germany; 526^th forward Support Battalion, Fort Campbell; and the United States Sergeants Major Academy at Fort Bliss.

After attending the Sergeants Major Academy, Class 51, CSM Gaines served as a Sergeant Major/Command Sergeant Major for the Support Operations for the 101^st Corps Support Group, Fort Campbell. He then served as the Command Sergeant Major for the Assistant Chief of Staff, Installation Management, Installation Management Command, Headquarters, Department of the Army, the Pentagon.

In addition, CSM Gains has been on several deployments which include, Multi-National Forces and Observes, El Gorah Egypt; Operation Uphold Democracy, Hati; Implementation Force, Bosnia; and Responsible Reset Task Force, Camp Arifjan Kuwait.

In his final active-duty assignment, CSM Gaines served as the Senior Enlisted Advisor for the Defense Commissary Agency, Fort Lee, Virginia.