Sergeant Major Thornton enlisted into the Marine Corps in October of 1984 and completed recruit training at MCRD Parris Island, SC in January of the following year. Upon completion of recruit training he reported to Fort Sill, Oklahoma for initial training and follow on assignment as an Artillery Fire Control Man. In March of 1985, Sergeant Major Thornton reported to Headquarters Battery, 5th Battalion, 10th Marines, Camp Lejeune, NC where he served as a surveyor, Battalion Training NCO and Assistant Battalion Operations Chief. In March of 1989, Sergeant Major Thornton transferred to Alpha Battery, 1st Battalion 12th Marines, Kaneohe Bay, Hawaii.
During this assignment, Sergeant Major Thornton held the billets of Computer Man, Battery Training NCO, Assistant Operations Chief and Operations Chief. Sergeant Major Thornton completed several unit deployments during this tour to include service in Operation Desert Shield and Desert Storm. In December of 1993, Sergeant Major Thornton completed the instructor course at Fort Sill OK and was assigned as a Fire Direction Control Man Instructor. In June of 1997, he received orders and reported to MCAGCC Twenty-Nine Palms, CA to serve as the 81mm Platoon Sergeant for 1st Battalion, 7th Marines. In June of 1999, Sergeant Major Thornton received orders to MCRD, Parris Island for duty as a drill instructor. During this tour, Sergeant Major Thornton served in Alpha, Charlie, Delta and Headquarters Companies holding the billets of Drill Instructor, Senior Drill Instructor, Series Gunnery Sergeant and Company First Sergeant.
In June of 2002, Sergeant Major Thornton was transferred to Camp Fuji, Japan serving as the Battalion Operations Chief and Headquarters Company First Sergeant. In March of 2003, upon his selection to First Sergeant, Sergeant Major Thornton transferred to Inspector-Instructor Staff, Waukegan, Il. Serving as the I&I 1stSgt, Family Readiness Officer and Station OIC during Weapons Company 2/24 deployment to IRAQ. In November of 2006, Sergeant Major Thornton was selected to his present rank and in March of 2007 was transferred to Marine Medium Helicopter Squadron 365 located at New River Air Station, NC for duty. During this assignment Sergeant Major Thornton served as the Air Combat Element Sergeant Major for the 24 MEU, OEF. In April 2009, Sergeant Major Thornton was transferred to Marine Aviation Logistics Squadron 29 serving as the Squadron Sergeant Major.
In August 2010, Sergeant Major Thornton assumed duties as the Marine Detachment Sergeant Major, Fort Sill, OK. Sergeant Major Thornton’s personal decorations include the Bronze Star, Meritorious Service Medal, Navy and Marine Corps Commendation Medal, Army Commendation Medal, Navy Marine Corps Achievement Medal w/2 stars, and the Combat Action Ribbon