First Sergeant Peacock enlisted in the United States Marine Corps in November 2001, attending recruit training at Marine Corps Recruit Depot Parris Island, South Carolina, in December 2001. Upon completion, he reported to the Infantry Training Battalion at the School of Infantry - East, Camp Geiger, North Carolina, where he earned the primary MOS of 0311, Infantry Rifleman.|
In June 2002, First Sergeant Peacock was assigned to 1st Battalion, 3rd Marines in Kaneohe Bay, Hawaii. Shortly thereafter, he deployed to Okinawa, Japan, in support of Operation Enduring Freedom – Philippines. In July 2004, he deployed once again, this time with the 31st Marine Expeditionary Unit (Special Operations Capable) in support of Operation Iraqi Freedom. During November 2004, he served as Assistant Team Leader for the Scout Sniper Platoon during Operation Phantom Fury, the Battle of Fallujah. Following the battle, he participated in operations in Rutba, Iraq, in support of the first democratic elections.
From January 2006 to January 2010, First Sergeant Peacock was assigned to Instructor Battalion at The Basic School (TBS). He was subsequently reassigned to the Infantry Officer Course (IOC) as an enlisted instructor and logistics chief.
In 2010, First Sergeant Peacock transitioned to the Marine Corps Reserves, first serving with Weapons Field Training Battalion, Quantico, Virginia, as part of the Individual Mobilization Augmentee (IMA) program. In 2011, he was promoted to Staff Sergeant and joined the IMA detachment at Marine Corps Intelligence Activity, Quantico, serving as a weapons and technology analyst and operations chief.
In 2015, he joined the IMA detachment at Marine Corps Systems Command, Quantico, and was mobilized as a contingency operations manager and SNCOIC of the newly formed Cyber Acquisitions Team.
In 2019, First Sergeant Peacock was promoted to Gunnery Sergeant and joined Marine Corps Advisor Company - Alpha, Washington, D.C., serving as an infantry tactics advisor to Central Europe and as Operations and Training Advisor. During this assignment, he earned the MOS 0570, Marine Advisor.
In 2023, he was promoted to his current rank of First Sergeant and assigned to Landing Support Company, Combat Logistics Regiment 45, Savannah, Georgia, later transitioning to Littoral Distribution Company Alpha, where he served as Company First Sergeant.
In 2026, First Sergeant Peacock was assigned as Senior Enlisted Leader for Supply Company, 4th CRR, in Albany, Georgia.
First Sergeant Peacock is a graduate of the University of Maryland University College, holding a Bachelor of Arts in Homeland Security with a minor in History. His personal decorations include the Navy and Marine Corps Commendation Medal, Navy and Marine Corps Achievement Medal, Combat Action Ribbon, and several other service and campaign medals.