Sergeant Major Johnson reported to MCRD Parris Island, South Carolina for recruit training in August 1993. Upon graduation, he completed Marine Combat Training and Field Radio Operators Course at 29 Palms, California. In April 1994, Private First Class Johnson was assigned to 1st Air Naval Gunfire Liaison Company (ANGLICO) Camp Pendleton, California. While stationed at 1st ANGLICO, he served in the billets as a Field Radio Operator, Fire power Control Team (FCT) Chief, and Supporting Arms Liaison Team (SALT) Chief. He was promoted up to the rank of Sergeant while assigned to 1st ANGLICO. Sergeant Johnson requested orders for Drill Instructor duty and he reported to Drill Instructor School, MCRD Parris Island, South Carolina in January 1999. Upon graduating, Sergeant Johnson served as Drill Instructor and Senior Drill Instructor for Company I, 3rd Recruit Training Battalion and as a Marine Combat Instructor of Water Survival (MCIWS).
In June 2002, Staff Sergeant Johnson received orders to 2nd Force Reconnaissance Company, Camp Lejeune, North Carolina. While serving here he held the billets of Radioman, Assistant Team Leader, and Electronic Key Management System (EKMS) manager. In January 2003, his platoon deployed in support of Operation IRAQI FREEDOM and after returning from deployment, his platoon then attached to the 22nd Marine Expeditionary Unit and deployed in support of Operation ENDURING FREEDOM in January 2004.
Gunnery Sergeant Johnson executed orders in June 2005 and reported to the Virginia Military Institute (VMI) for duty as the Assistant Marine Officer Instructor (AMOI). While stationed at VMI, he augmented during the summer at Officer Candidates School as a Sergeant Instructor in 2005 and as a Platoon Sergeant in 2007. In May 2008, Gunnery Sergeant Johnson received the "Leadership Mentor Award" voted on by the Corps of Cadets.
In July 2008, Gunnery Sergeant Johnson received orders to 8th Communications Battalion, Camp Lejeune, North Carolina and held the billet of Radio Platoon Sergeant and Company Assistant Operations Chief. He was selected to First Sergeant and reported to Company C, 1st Battalion, 9th Marines "The Walking Dead". He was deployed with the 24th Marine Expeditionary Unit where they conducted Humanitarian Assistance in Haiti after the earthquake. After deployment, he then deployed with Weapons Company to Nawa and Trek Nawa, Afghanistan in support of Operation ENDURING FREEDOM.
In February 2012, First Sergeant Johnson received orders to 2d Intelligence Battalion and served in the duties as Company First Sergeant for Production and Analysis Company (PACO), Production and Analysis Support Company (PASCO), and Company G. He also served as the Company First Sergeant for Company G, Officer Candidates School, Quantico, Virginia from May to August 2013.
In February 2014, Sergeant Major Johnson received orders to Marine Attack Training Squadron 203 in Cherry Point, North Carolina to serve as the Squadron Sergeant Major until he executed orders in January 2016 to Recruiting Station Atlanta. From March 2018 to August 2020, he served as the Sergeant Major of Marine Aircraft Group 12 in Iwakuni, Japan.
In September 2020, Sergeant Major Johnson assumed the post of Sergeant Major for 24th Marine Expeditionary Unit, II Marine Expeditionary Force.
Sergeant Major Johnson's personal awards include the Meritorious Service Medal with three gold stars, Navy and Marine Corps Commendation Medal with one gold star, Navy and Marine Corps Achievement Medal with one gold star, Combat Action Ribbon with one gold star, Military Outstanding Volunteer Service Medal, and the Navy and Marine Corps Parachutist Insignia.