Sergeant Major Mangrum attended recruit training in August 1994 at Marine Corps Depot San Diego, California. Following recruit training and Marine Combat Training, he attended Basic Vehicle Repair Course at Assault Amphibian Schools Battalion Camp Pendleton, California, earning the MOS of 2141, AAV Repairman.
Following school, then Private First Class Mangrum was assigned to Combat Assault Company, 3d Marine Regiment, Marine Corps Base Kaneohe Bay, Hawaii. While stationed in Hawaii, he deployed in support of exercises Foal Eagle ’95, Tafakula ’96, and CARAT ’97.
In September 1998, then Sergeant Mangrum was then assigned to the Inspector-Instructor Staff, Company A, 4th Assault Amphibian Battalion Norfolk, Virginia.
After his tour was complete in July 2002, then Staff Sergeant Mangrum was assigned to Company A, 2d Assault Amphibian Battalion Camp Lejeune, North Carolina where he served in the billets of Platoon Sergeant and Recovery Chief. He also deployed with Task Force Tarawa and participated in Operation Enduring Freedom and Operation Iraqi Freedom.
Upon return from deployment, then Staff Sergeant Mangrum attended Marine Security Guard School where he was the SNCO honor graduate. Following school in September 2004, Staff Sergeant Mangrum was assigned as the Detachment Commander at U.S. Embassies Tunis, Tunisia; Phnom Penh, Cambodia; and Tokyo, Japan. He also served as an Instructor/Advisor at Marine Security Guard School. While at Marine Security Guard School, then Gunnery Sergeant Mangrum attended the Advanced Course where he was the honor graduate.
Following selection and promotion in April 2009, then First Sergeant Mangrum was transferred to 1st Battalion, 2d Marines Camp Lejeune, North Carolina where he served as Company First Sergeant for Companies C and H&S. He also deployed in support of Operation Enduring Freedom in Afghanistan and as the Battalion Landing Team for the 24th Marine Expeditionary Unit.
In February 2013, then First Sergeant Mangrum was transferred to 2d Supply Battalion Camp Lejeune, North Carolina where he served as the Company First Sergeant of Supply Company. He also attended Senior Enlisted PME course where he received the Sergeant Major of the Marine Corps Writing Award.
In December 2014, Sergeant Major was selected to his current rank and transferred to Marine Fighter Attack Squadron 314, Marine Corps Air Station Miramar, California where he served as the Squadron Sergeant Major. While assigned to Miramar, Sergeant Major Mangrum deployed in support of the Unit Deployment Program to Iwakuni, Japan.
From July 2017 to June 2018 Sergeant Major Mangrum attended Marine Corps University’s Command and Staff College where he was awarded a Masters of Military Studies degree.
Following Command and Staff College, Sergeant Major Mangrum assumed the post of 15th MEU Sergeant Major, where he currently serves.
Sergeant Major Mangrum holds an Associate’s Degree in General Studies from Central Texas College, a Bachelor’s Degree in Management Information Systems from Ashford University, and a Master’s Degree in Military Studies from Marine Corps University’s Command and Staff College.
Sergeant Major Mangrum’s personal awards include: Meritorious Service Medal with two stars, the Navy and Marine Corps Commendation Medal with Combat Distinguishing Device and one star, the Navy and Marine Corps Achievement Medal with two stars, and the Combat Action Ribbon with one star.