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MCRD Parris Island


MCRD Parris Island

Eastern Recruiting Region

"We Make Marines"
Sgt. Maj. Jason D. DiCosimo Sergeant Major, 1st Recruit Training Battalion

Sergeant Major DiCosimo was born and raised in New Britain, CT. He enlisted in January 1998 and underwent recruit training at Fox Company, 2nd Recruit Training Battalion, Marine Corps Recruit Depot, Parris Island, S.C.

In June 1998, Sergeant Major DiCosimo completed Utilities Instruction Course at Engineer School, Courthouse Bay, Camp Lejeune, N.C. He was ordered to MACS-1 Engineers, Yuma, AZ for duty. He served in a variety of billets from Team Leader to Squad Leader.

Sergeant Major DiCosimo was transferred in November 2000 to 9th Engineer Support Battalion aboard Camp Hansen, Okinawa, Japan where he was promoted to Corporal meritoriously. He was assigned as Squad Leader and was deployed to Korea. He was then promoted to the rank of Sergeant.

In December 2001, Sergeant Major DiCosimo was assigned to MTACS-38 Engineer Platoon where he assumed the responsibilities as Platoon Sergeant. In November 2002, he deployed forward to Kuwait then on to Iraq in Support of Operation Internal Look, Operation Southern Watch, and Operation Iraqi Freedom 1.

In March 2004, Sergeant Major DiCosimo received orders to Drill Instructor School, Marine Corps Recruit Depot, Parris Island, SC. Upon completion of Drill Instructor School, he was assigned to Company A, 1st Recruit Training Battalion. He served as a Drill Instructor, Experienced Drill Instructor, Senior Drill Instructor, Marine Combat Instructor of Water Survival and Chief Drill Instructor. He was then promoted to Staff Sergeant in 2006.

In April 2007, Sergeant Major DiCosimo was ordered to MWSS-371 Engineer Operations Company in Yuma, AZ. He served as Platoon Sergeant and Company First Sergeant.  He was assigned as the Antiterrorism and Force Protection Chief as well as Engineer Coordinator for his next deployment to Iraq in June 2008.

In April 2010, Sergeant Major DiCosimo was selected for duty as a Drill Instructor for Navy Officer Candidate School in Newport, RI.  He served as Class Drill Instructor, Regimental Drill Master, Regimental Physical Fitness Coordinator and First Battalion SNCOIC. He was then promoted to Gunnery Sergeant.

Upon completion of his tour at Navy Officer Candidate School in April 2013, Sergeant Major DiCosimo was then assigned to MWSS-374 Engineer Company in 29 Palms, CA. He held the billets of Operations Chief, Platoon SNCOIC and Platoon Commander.

In September 2014, he was promoted to First Sergeant and received orders to Company I, 3d Battalion 7th  Marines in 29 Palms, CA. With Company I, he deployed as the Crisis Response, Tactical Recovery of Aircraft and Personnel Helicopter-Company 1stSgt with the Special Purpose Marine Air Ground Task Force/ Operation Inherent Resolve to Kuwait and Iraq.

In February, 2016 he received orders to Company B, 1st Battalion, 25th Marines to serve as Inspector – Instructor 1stSgt. He has served as the Inspector-Instructor, Inspector-Instructor 1stsgt, and the Company 1stSgt. In June of 2018, he was promoted to his current rank of Sergeant Major and received orders to First Recruit Training Battalion to serve as the Battalion Sergeant Major. 

Sergeant Maj. DiCosimo and his wife Yvonne have two sons, Jacob and James

His personal awards include the Navy Marine Corps Commendation Medal with two gold star, the Navy Marine Corps Achievement Medal with three gold stars and the Military Outstanding Voluntary Service Medal.