Captain Justin Shupe enlisted in the Selected Marine Corps Reserve in October 2014. Upon completing recruit training at Marine Corps Recruit Depot San Diego, Marine Combat Training, and the Cannon Crewman Course, he earned military occupational specialty (MOS) 0811, Field Artillery Cannoneer, and was meritoriously promoted to Lance Corporal after graduating first in his class.
In September 2015, Lance Corporal Shupe reported to Quebec Battery, 5th Battalion, 14th Marines, where he served as an artillery cannoneer. He was meritoriously promoted to Corporal in September 2016 and later served as a gunner on his cannon section. In January 2018, Corporal Shupe attended the Artillery Training School Section Chief Course at 1st Battalion, 11th Marines. Upon graduation, he returned to Quebec Battery and served as a section chief during Integrated Training Exercise (ITX), the Korean Marine Exchange Program (KMEP), and a joint exercise with the U.S. Army at Fort Bliss, Texas. He was promoted to Sergeant in July 2018 and later served as the battery's base piece chief for the next two years. While serving in the Selected Marine Corps Reserve, he earned a Bachelor of Science in Mechanical Engineering from the University of Colorado Denver.
In January 2021, Sergeant Shupe reported to Officer Candidates School. Upon commissioning as a Second Lieutenant, he attended The Basic School followed by the Marine Artillery Officer Basic Course, earning MOS 0802, Field Artillery Officer.
In May 2022, Second Lieutenant Shupe reported to Fox Battery, 2d Battalion, 14th Marines, where he served as the Remain Behind Element Officer in Charge while the battery was deployed on the Unit Deployment Program. Following the unit's return in November 2022, he assumed duties as Third Platoon Commander. Throughout his time at Fox Battery, he served as Fire Direction Officer during annual training at Fort Cavazos, Texas, Arctic Edge 24, and Weapons and Tactics Instructor (WTI) Course 2-26.
Promoted to Captain in October 2025, he assumed duties as Battery Executive Officer and later served a two-month period as the interim Commanding Officer of Fox Battery. As Executive Officer, he helped lead the battery through three annual training exercises across five countries alongside partner nation militaries.
In July 2026, Captain Shupe assumed command of Kilo Battery, 2d Battalion, 14th Marines in Huntsville, Alabama.
Captain Shupe's decorations include the Navy and Marine Corps Achievement Medal (three awards), the Selected Marine Corps Reserve Medal (three awards), and the Armed Forces Reserve Medal.
In his civilian career, Captain Shupe owns a hardwood flooring company in Colorado, where he has employed Marines and military veterans for more than a decade. He is a native of Bayfield, Colorado.