Sergeant Major Pinkerton enlisted in the Marine Corps on 29 November 1992, and attended recruit training at Marine Corps Recruit Depot Parris Island, South Carolina. Upon completion, he received training at Motor Transport School, Camp Johnson, North Carolina, where he received the Military Occupational Specialty of Motor Transport Operator.
Following Motor Transport School, Sergeant Major Pinkerton reported to Service Company, Headquarters Battalion, 1st Marine Division, Camp Pendleton, California. He was then reassigned to Truck Company, Headquarters Battalion, 3rd Marine Division, Okinawa Japan in July 1995. In November 1996, Sergeant Major Pinkerton received orders to Marine Wing Support Squadron 372, Camp Pendleton, California.
Sergeant Major Pinkerton attended Basic Recruiter Course, Marine Corps Recruit Depot, San Diego, California in June 1999. Upon graduating, Sergeant Major Pinkerton received orders to Recruiting Station Orange, Recruiting Sub-Station Redondo Beach, California.
In October 2002, Sergeant Major Pinkerton reported to Truck Company, Headquarters Battalion, 1st Marine Division, Camp Pendleton, California. During this assignment Sergeant Major Pinkerton deployed in support of Operation Iraqi Freedom (OIF) I, II and III.
In December 2005, Sergeant Major Pinkerton was reassigned to Logistics Operations School, Camp Johnson, North Carolina, where he remained until December 2008, when he was transferred to 1st Battalion 12th Marines, 3rd Marine Division, Marine Corps Base Hawaii.
In December 2010, Sergeant Major Pinkerton received orders to India Company, 3rd Battalion, 3rd Marines, 3rd Marine Division, Marine Corps Base Hawaii. During this assignment Sergeant Major Pinkerton deployed twice in support of OEF.
Sergeant Major Pinkerton reported to Alpha Battery, 1st Battalion, 12th Marines, 3rd Marine Division, Marine Corps Base Hawaii in June 2012, and was then transferred to Service Company, Headquarters Battalion, Marine Corps Base Hawaii in April 2014.
In February of 2015, Sergeant Major Pinkerton was promoted to his current rank and assigned to 2nd Battalion, 5th Marines, 1st Marine Division, where he deployed twice in support of the 31st Marine Expeditionary Unit.
In August of 2017, Sergeant Major Pinkerton was assigned to his current billet 1st Intelligence Battalion Sergeant Major.
Sergeant Major Pinkerton has received the Bronze Star Medal with combat distinguishing device, the Meritorious Service Medal (second award), the Navy and Marine Corps Commendation Medal with combat distinguishing device (third award), the Navy and Marine Corps Achievement Medal (second award), and the Combat Action Ribbon (second award).