Private First Class Shaffer enlisted in the Marine Corps RSS Altoona, Pennsylvania and reported for recruit training at Marine Corps Recruit Depot Parris Island, South Carolina, on 17 November 1997. Upon completion of recruit training, he reported to Camp Geiger, North Carolina for Marine Combat Training. Upon Completion of Marine Combat training he reported to Camp Johnson, North Carolina for Basic Warehousing Course and was assigned the MOS of 3051 Warehouse Clerk.
In April 1998, upon successful completion of MOS school, Private First Class Shaffer reported to Camp Lejeune, North Carolina for service with 2d Force Service Support Group, 2d Supply Battalion, 2d Supply Company for duty as a warehouse clerk. In May 2000, he was promoted to the rank of Corporal and was assigned as the NCOIC for Storage Operations. In November 2001, he was promoted to the rank of Sergeant and served as Platoon Sergeant of Storage Platoon. In June 2002, he reported to MCRD, San Diego for Recruiting School and was assigned to Recruiting Station Charleston, West Virginia, Recruiting Sub-Station Xenia as a Canvassing Recruiter. In January 2005, he was meritoriously promoted to Staff Sergeant.
In June 2006, he reported to MCAS Cherry Point, Marine Air Control Group 28, Marine Tactical Air Control Squadron 28 (MTACS-28), he held billets of Supply Officer, Supply Chief, Warehouse Chief and Equal Opportunity Representative. In July 2007, he deployed to Iraq with MTACS-28 and again in January 2009.
In May 2010, he reported to Okinawa, Japan, for service with 3d Marine Logistics Group, 3d Supply Battalion, 3d Supply Company. In July 2010, he was promoted to the rank of Gunnery Sergeant and held billets as Warehouse Chief, Guard Chief, Operations Chief and Company Gunnery Sergeant. In May 2013, he was transferred to Joint Base Fort Story, Virginia Beach, Virginia for service at Marine Corps Security Cooperation Group as a Coordination Liaison Assessment Training Team member, while assigned to MCSCG he attended the Defense Language Institute satellite office on Dam Neck, Virginia to study Modern Standard Arabic.
In September 2014, he was selected to his current rank and assigned to Camp Lejeune, North Carolina for duty at 8th Communication Battalion, Company C and Company A. In March 2017, he was transferred to Twenty-nine Palms, California, for service at Marine Corps Communications Electronics School, Air Control Training Squadron as the Senior Enlisted Advisor. First Sergeant Shaffer’s professional military education includes the United States Marine Corps Senior Enlisted Primary Military Education Course.