Sergeant Major Matthew A. Dorsey enlisted in the Marine Corps in February 1998 and attended recruit training at 3d Recruit Training Battalion, Marine Corps Recruit Depot, San Diego, California. Sergeant Major Dorsey reported to the Basic Motor Transport Mechanics Course at Camp Johnson, North Carolina earning the military occupational skill (MOS) of 3521. He reported for duty with 3d Material Readiness Battalion, Motor Transport Maintenance Company, Camp Kinser, Okinawa, Japan where he deployed to Korea while attached to Combat Service Support Detachment-29 supporting Alert Contingency Marine Air Ground Task Force (MAGTF) operations.
In October 2000, Sergeant Major Dorsey reported to 3d Marine Aircraft Wing, Marine Tactical Air Command Squadron 38 where he was promoted to Sergeant and served as the Maintenance Chief, Platoon Sergeant, and Squadron Color Sergeant. In January 2003 Sergeant Major Dorsey deployed in Support of Operation Enduring Freedom and Operation Iraqi Freedom. In January 2004 Sergeant Major Dorsey reported to Drill Instructor School Marine Corps Recruit Depot San Diego as a student. In March he reported to Kilo Company, 3d Recruit Training Battalion for duty as a Drill instructor. He completed 8 cycles total serving as a Drill Instructor, Senior Drill Instructor, then as an instructor of water survival.
In March of 2007 Sergeant Major Dorsey reported to 1st Maintenance Battalion, Repairable Management Company, Camp Pendleton, California. He served as the Engines and Transmission rebuild floor chief. In 2008 he deployed back to Iraq in Support of Operation Iraqi Freedom where he served as the Motor Transport Chief and Dynamometer Chief for all maintenance assets within the company. In April 2010 Sergeant Major Dorsey reported to 4th Maintenance Battalion, General Support Maintenance Company, Rock Island, Illinois as part of the Inspector & Instructor Staff. In September he was promoted to Gunnery Sergeant and served as the Organics Maintenance Chief, Equal Opportunity Representative, Arms Ammunition and Explosives Officer, Anti-Terrorism Officer, Toys for Tots Coordinator, and the Motor Transport Licensing Examiner, and completed his tour serving as the Company First Sergeant.
In August 2013 Sergeant Major Dorsey transferred to Logistics Operational School, Marine Corps Combat Service Support Schools where he served as an instructor for the Advanced Ground Transportation Operational Support Section. In February 2014 he was frocked to the rank of First Sergeant and transferred to 3d Battalion, 2d Marines, 2d Marine Division, Camp Lejeune, North Carolina. During his time there he served as First Sergeant for Company K where he deployed in support of the Unit Deployment Program 2-15 to Korea, the Philippines, and Okinawa, Japan. Following that deployment he was re-assigned to Weapons Company where he re-deployed with the battalion in support of the Unit Deployment Program 2-16 back to Okinawa, Japan. In July 2017 Sergeant Major Dorsey transferred to Headquarters Regiment, 1st Marine Logistics Group, Camp Pendleton, California where he served as company First Sergeant for Headquarters Company. During this period he also fulfilled the duties as the Battalion Sergeant Major for Combat Logistics Battalion 11.
In February 2018 Sergeant Major Dorsey was frocked to his current rank of Sergeant Major and assigned 1st Battalion 5th Marines, 1st Marine Division, Camp Pendleton, California. During his tour he deployed as the Battalion Landing Team (BLT) Sergeant Major in support of the 31st Marine Expeditionary Unit. During this deployment BLT 1/5 supported operations in the Pacific including Exercise Cobra Gold-20. Following that deployment, he re-deployed with 1st Battalion 5th Marines as part of the Special Purpose MAGTF-Customs Border Patrol in support of the Southwest Border Mission.
In December 2020 Sergeant Major Dorsey transferred to his current assignment as Battalion Sergeant Major of Support Battalion, Recruit Training Regiment, Marine Corps Recruit Depot, San Diego California. Sergeant Major Dorsey's personal awards include the Meritorious Service Medal, the Navy Commendation Medal with 2 gold stars in lieu of third award, and the Navy and Marine Corps Achievement Medal with 3 gold stars in lieu of fourth award.