Sergeant Major Denham enlisted in the Marine Corps on June 2, 1992 and completed recruit training at MCRD Parris Island, South Carolina. After completion of recruit training he attended The School of Infantry East at Camp Geiger, where he was assigned the 0352 Anti-Tank Assault Guided Missleman MOS.
In January 1993, Private First Class Denham reported to 2nd Battalion, 2nd Marine Regiment, Camp Lejeune, North Carolina. During this tour, he fulfilled duties as Gunner, Team Leader, and Section leader while deploying three times. He completed a UDP to Okinawa, deployed with the SPMAGTF to Haiti in support of Operation Support/Uphold Democracy and deployed to the Mediterranean Sea with the 22nd MEU supporting Operation Joint Endeavor, Assured Response, and Quick Response. During that assignment from January 1993 to October 1996, he was promoted to Lance Corporal, and subsequently to Corporal.
In October 1996, Corporal Denham was transferred to the School of Infantry East, Infantry Training Battalion for duty as an Instructor. He was assigned to Alpha Company where he instructed the 0352, 0351, and 0311 MOS courses. He was then transferred to Weapons Company to serve as a 0352 instructor. In November 1996, he was promoted to the rank of Sergeant.
In November 1999, Sergeant Denham left the Marine Corps upon completion of his tour at SOI. In January 2000, Sergeant Denham returned to the Marine Corps for duty with Lima Company, 3rd Battalion, 23rd Marines as part of the Select Marine Corps Reserve. During this assignment he held the billets of Assault Section Leader, Mortar Section Leader, Platoon Sergeant, Platoon Commander, and Company Gunnery Sergeant. He also deployed to Operation Iraqi Freedom twice.
In July 2008, Gunnery Sergeant Denham returned to active duty and reported to 3rd Battalion, 3rd Marine Regiment, Marine Corps Base Hawaii for duty as the Kilo and India Company Gunnery Sergeant. During this tour he deployed once more to Iraq and once in support of Operation Enduring Freedom. During the Iraq deployment, Gunnery Sergeant Denham took part in the personnel recovery of Captain Michael S. Speicher who was shot down during the Gulf War.
In August 2011, Gunnery Sergeant Denham reported to MCRD Parris Island for duty with Weapons and Field Training Battalion where he initially fulfilled the duties of Operations Chief and Platoon Sergeant. In October 2012, he was promoted to First Sergeant and was assigned as the Field Training Company First Sergeant.
In June of 2014 First Sergeant Denham reported to 2D Law Enforcement Battalion at Camp Lejeune, N.C. where he served as the First Sergeant for Charlie Company and Headquarters and Support Company. In April 2017 SgtMaj Denham was assigned as the Battalion Sergeant Major for 3d Battalion 1st Marines. Sergeant Major Denham served as the Battalion Landing Team Sergeant Major with the 13th Marine Expeditionary Unit and during the Battalion’s deployment to the South West Border as part of the SPMAGTF- CBP. SgtMaj Denham currently serves as the Group Sergeant Major for Marine Air Control Group-28
Sergeant Major Denham’s personal awards include the Meritorious Service Medal with one gold star, Navy and Marine Corps Commendation Medal with one gold star and combat distinguishing device, Navy and Marine Corps Achievement Medal with three gold stars, and the Combat Action Ribbon with one gold star.