Sergeant Major Phillip R. Kirkham enlisted in the Marine Corps in July of 2002. He completed recruit training at Marine Corps Recruit Depot Parris Island, South Carolina. Following recruit training, he attended Infantry Training Battalion at Camp Geiger, North Carolina, where he earned the military occupational specialty of 0311, Infantry Rifleman.
In January of 2003, he was assigned to India Company, 3rd Battalion, 2nd Marines, Camp Lejeune, North Carolina, where he served as a gunner for the 60-millimeter mortar section. In January 2003, he deployed with 3rd Battalion, 2nd Marines, as part of the Task Force Tarawa to Kuwait and Iraq. While deployed he took part in the Battle of Nasiriyah. In April of 2003, he was promoted to Lance Corporal. In 2004, he deployed to Djibouti, Africa as part of the Anti-Terrorism Battalion, where he served as a squad leader for the mortar section. He again deployed in February of 2005 to Husaybah, Iraq in the Al Anbar Province. In August of 2005, he was promoted to Corporal.
In December of 2005, he reported to Weapons Field Training Battalion, Marine Corps Base Quantico, Virginia, where he assumed the duties of Combat Marksmanship Coach and Combat Marksmanship Trainer. In June of 2007, he was promoted to the rank of Sergeant. In August of 2008, he was assigned to Lima Company, 3rd Battalion, 9th Marines, Camp Lejeune, North Carolina, where he served as a rifle squad leader. In July of 2009, he deployed with 3rd Battalion, 9th Marines in support of Operation Iraqi Freedom. In October of 2010, he deployed to Marjah, Afghanistan in support of Operation Enduring Freedom.
In July of 2012, he reported to Drill Instructor School-East, Marine Corps Recruit Depot Parris Island. Subsequently he was assigned to Bravo Company, 1st Recruit Training Battalion where he served as a Drill Instructor, Senior Drill Instructor, and Chief Drill Instructor. In January of 2013, he was promoted to the rank of Staff Sergeant.
In July of 2015, he was assigned to Weapons Company, 1st Battalion, 7th Marines, Marine Corps Air Ground Combat Center Twentynine Palms where he served as a Combined Anti-Armor Team Platoon Sergeant. In October of 2015 and April of 2017, he deployed to Al Asad Air Base, Al Anbar, Iraq in Support of Operation Inherent Resolve 16.1 and 17.2 as part of the Marine Detachment Task Force-Al Asad Security. In January of 2017 he was promoted to the rank of Gunnery Sergeant.
In June of 2018, he reported to Drill Instructor School-West, Marine Corps Recruit Depot San Diego. Subsequently, he was assigned to Alpha Company, 1st Recruit Training Battalion where he served as a Chief Drill Instructor. In February of 2019, he was assigned to Drill Instructor School-West where he served as Squad Instructor, Academic Instructor, and Chief Instructor. In April of 2021, he was promoted to the rank of First Sergeant.
In May of 2021, he was assigned to 1st Transportation Battalion where he served as the Unit Senior Enlisted Leader for Company A, and Headquarters and Service Company. In December of 2022, he was assigned to 1st Intelligence Battalion where he served as the Unit Senior Enlisted Leader for Combat Service Support Company, I Marine Expeditionary Force Support Battalion, and Headquarters Company, 1st Intelligence Battalion.
In August of 2025, he was promoted to the rank of Sergeant Major and assigned to Marine Heavy Helicopter Squadron 361 where he serves as the Command Senior Enlisted Leader.
Sergeant Major Kirkham's personal decorations include the Navy and Marine Corps Commendation Medal with three gold stars, the Navy and Marine Corps Achievement Medal with two gold stars, and Combat Action Ribbon with one gold star.