Sergeant Major Chapman enlisted in the Marine Corps on June 27th 1983 and reported to MCRD Parris Island, South Carolina. Upon graduation from the 3rd Recruit Training Battalion he was assigned to Basic Combat Engineer School and received training as a Basic Combat Engineer (1371).

Sergeant Major Chapman received orders to report to 3rd Combat Engineer Battalion, Okinawa, Japan in Nov. 1983.

Sergeant Major Chapman reenlisted in June 1985 and transferred to 2nd Combat Engineer Battalion.  While serving with the Battalion he filled the billet of squad leader.  He deployed in the fall of 1985 with Battalion Landing Team, 3rd Battalion, 2nd Marine Regiment and again with BLT 1st Battalion, 2nd Marine Regiment.

Sergeant Major Chapman was promoted to the rank of sergeant in June 1987 and deployed with 3rd Battalion, 8th Marine Regiment to Panama in October 1988. Upon return from his deployment, he was assigned to the Engineer Training Area, Camp Lejeune as the chief demolitions instructor.

Sergeant Major Chapman received orders to Drill Instructors School in June 1990.  Upon graduation he was assigned to 2nd Recruit Training Battalion where he served as a drill instructor / senior drill instructor until June 1992.

Sergeant Major Chapman received orders back to 2nd Combat Engineer Battalion in July 1992.  While assigned to the Battalion he served as a platoon guide and platoon sergeant.  During this time Sergeant Major Chapman deployed to Somalia with BLT 1/2 in Nov. 1993.  Upon return from his deployment, he was selected to the rank of staff sergeant and received orders to Marine Barracks Cuba, Minefield Maintenance Platoon in June 1994.

Sergeant Major Chapman was then assigned to the Staff Noncommissioned Officers Academy, where he served as an instructor with both the Sergeants Course and the Career Course.  Selected to the rank of gunnery sergeant he received orders back to 2nd Combat Engineer Battalion in June 1998.

Sergeant Major Chapman served as the company gunnery sergeant and first sergeant for Company C. Sergeant Major Chapman deployed with BLT 1/8 in 2000.  Upon return from deployment he was selected to first sergeant and received orders to 2nd Amphibious Assault Battalion in May 2001.

Sergeant Major Chapman was assigned as the first sergeant for Company B and deployed to Iraq in support of 1st Battalion, 7th Marine Regiment in 2003.  Upon returning in 2004, he was assigned as the first sergeant for Headquarters and Support Company.  Selected to Sergeant Major in 2004 he received orders to 3rd Marine Logistics Group and served as the Battalion Sergeant Major for Combat Logistics Battalion (CLB-31). Upon completion of his tour he received orders to I&I Staff, 3rd Battalion, 25th Marine Regiment in Brookpark, Ohio.

Sergeant Major Chapman joined the 22nd Marine Expeditionary Unit in December 2009 and deployed to Haiti in support of Operation Unified Response.