Sergeant Major Jason R. Cain enlisted in the Marine Corps in March 1993 and underwent recruit training at 2nd Recruit Training Battalion, Echo Company, Marine Corps Recruit Depot, Parris Island, South Carolina. In August 1993, Private First Class Cain completed Marine Combat Training and School of Infantry at Marine Corps Base, Camp Geiger North Carolina. He reported to 3rd Battalion, 2nd Marines, Camp Lejeune North Carolina, for duty. He served in a variety of billets from Ammunition Man to Assistant Operations Chief. He deployed on four separate occasions and participated in numerous operations. In October 1999, Sergeant Cain received orders to Drill Instructor School, Marine Corps Recruit Depot, Parris Island, South Carolina. Upon completion of Drill Instructor School, he was assigned to Company G, 2nd Recruit Training Battalion, as a Drill Instructor, Experience Drill Instructor, and Senior Drill Instructor. In May 2001, Staff Sergeant Cain was transferred to 3rd Battalion, 8th Marines and held the billets of Platoon Sergeant to Company Gunnery Sergeant. He completed a Unit Deployment Program in Okinawa, Japan and deployed to Iraq in support of OIF 2-2/4-6. In January 2006, Staff Sergeant Cain reported to the Camp Lejeune SNCO Academy, as an instructor for the Sergeants, Career, and Advanced Course decks during his tenure. In January 2009, Gunnery Sergeant Cain was transferred to 3rd Battalion, 2nd Marines, Camp Lejeune, North Carolina, for duty as the Company Gunnery Sergeant for Kilo Company. He deployed with the 22nd Marine Expeditionary Unit and participated in numerous exercises in the Persian Gulf and Haiti in support of Operation Unified Response. In April 2010, First Sergeant Cain was assigned to Headquarters and Service Company. First Sergeant Cain reported to Marine Detachment in Fort Bliss, Texas, from August 2010 to August 2012, as the final detachment First Sergeant of the Low Altitude Air Defense Gunners schoolhouse.
From September 2012 to February 2015, First Sergeant Cain was assigned to Bravo Company, 1st Light Armored Reconnaissance Battalion, Camp Pendleton, California, as the Company First Sergeant. He deployed to the Persian Gulf with the 13th Marine Expeditionary Unit. Sergeant Major Cain was assigned to 4th Tank Battalion, San Diego, as the Inspector-Instructor Sergeant Major from February 2015 to June 2017. Sergeant Major Cain’s personal decorations include the Purple Heart, Marine Corps Commendation Medal with two gold stars, Navy and Marine Corps Achievement Medal with Combat Distinguishing Device with three gold stars, and Combat Action Ribbon with one gold star.