Peter Hersey was commissioned a Second Lieutenant after completing NROTC at the George Washington University in Washington, D.C. Upon completion of The Basic School and Infantry Officers Course, Second Lieutenant Hersey reported to 3rd Battalion 6th Marines where he served as the assistant operations officer and platoon commander in support of Operation Iraqi Freedom in 2007 in Habbaniya, Iraq and again in 2008 as a company executive officer in Fallujah.
First Lieutenant Hersey then reported to 3d Reconnaissance Battalion and served in the Force Reconnaissance Company as a platoon commander from 2009 until 2011. During this time Major Hersey deployed twice on the 31st Marine Expeditionary Unit, participating in exercises in Japan, Philippines, Thailand and Guam. In May, 2011, Captain Hersey deployed as a reconnaissance company executive officer in support of Operation Enduring Freedom in the Upper Sangin Valley, Helmand Province, Afghanistan.
In summer 2012, Captain Hersey reported to the U.S. Training Mission to Saudi Arabia. He served as the infantry and special forces training advisor to the Saudi Arabian Marine Corps and Naval Special Forces for the Eastern Fleet in Jubail, Saudi Arabia.
In July 2013 he reported to 1st Battalion 1st Marines where he took command of Bravo Company and deployed to Sana’a, Yemen, to conduct site security for the U.S. Diplomatic Mission. Upon returning he led his company through a work-up and in the fall of 2014 deployed with his company again to Okinawa Japan on the Unit Deployment Program.
In July 2015 he checked in to the Combined Arms Training Center at Camp Fuji, Japan, where he served as the operations officer and after being promoted to major, as the executive officer.
In August 2017, Major Hersey checked into The Basic School and served as the section head of the command and maneuver sections. He then took command of Echo Company, Basic Officer Course 5-18 followed by India Company Warrant Officer Basic Course 1-19.
In July 2019, he reported to Task Force 51 / 5th Marine Expeditionary Brigade in Bahrain. He served as a current and future operations officer, supporting operations in 12 countries in the Central Command Area of Operation.
In July 2020, he reported to 3d Reconnaissance Battalion in Okinawa, Japan to serve as the executive officer. In April 2021 he assumed duty as the Commanding Officer of the Jungle Warfare Training Center, at Camp Gonsalves. Lieutenant Colonel Hersey’s decorations include the Meritorious Service Medal, the Navy-Marine Corps Commendation Medal with two Gold Stars, the Navy-Marine Corps Achievement Medal with two Gold Stars, and the Combat Action Ribbon with Gold Star.