Sergeant Major Kirkby is a native of LaFargeville, New York. He reported to Marine Corps Recruit Depot, Parris Island, SC for Basic Training in August of 1998. He was assigned Military Occupational Specialty of 0111 and reported to Personnel Administrative School, Camp Johnson, NC. Upon graduation he received orders to S1 Recruit Training Regiment, Marine Corps Recruit Depot, Parris Island, SC.
In November 2002, SgtMaj Kirkby was promoted to the rank of Sergeant and received Regimental Special Orders to serve as the Noncommissioned Officer-In-Charge for Recruit Processing Company, Support Battalion.
In July 2003, SgtMaj Kirkby reported as a student to Drill Instructor School, Parris Island, SC. Following graduation, he attended Marine Corps Martial Arts Green Belt Instructor Course training where he received his instructor tab. He was then assigned to Golf Company, Second Recruit Training Battalion where he served as a Drill Instructor, Senior Drill Instructor, and a Series Gunnery Sergeant. In January 2006 he was Special Duty Assignment selected for and meritoriously promoted to the rank of Staff Sergeant.
In February 2007, SgtMaj Kirkby reported to Camp Courtney, 3D Marine Division, Okinawa, Japan where he served as the Division Staff Secretary Admin Chief, and later as the G1 Administrative Chief. In October 2008 he deployed as the Command Element Administrative Chief for 3D Marine Regiment to Kandahar, Afghanistan in support of the Special Purpose Marine Air Ground Task Force - Afghanistan. While deployed he was promoted to the rank of Gunnery Sergeant in March 2009. Upon redeployment, he was assigned as the 3D Marine Division, G1 Adjutant Chief.
As his Okinawa tour was coming to an end, he was selected to serve as the Assistant Marine Officer Instructor (AMOI) for the Naval ROTC Cornell University. While assigned as the AMOI he spent his summers at Officer Candidate School where he served as a Sergeant Instructor and Platoon Sergeant Instructor for four different platoons.
In September 2013, SgtMaj Kirkby received orders to Headquarters and Headquarters Squadron, Marine Corps Air Station, Beaufort, SC where he was assigned as the Administrative Chief, Squadron Gunnery Sergeant, and for a period the Funeral Detail Staff Noncommissioned Officer-In-Charge. In the winter of 2014, he was selected to the rank of First Sergeant and promoted January 2015.
SgtMaj Kirkby reported to 1st Light Armored Reconnaissance Battalion, Camp Pendleton, CA in February 2015, where he was assigned as the First Sergeant for Diablo Company and deployed with 3rd Battalion, 1st Marines (V31), Battalion Landing Team, 15th Marine Expeditionary Unit aboard the USS Anchorage. Following deployment, he served as the company First Sergeant for Charlie Company and later as the Headquarters & Service Company First Sergeant. In the fall of 2018, he was selected for the rank of Sergeant Major, and promoted February 2019.
In February 2019, SgtMaj Kirkby reported for duty as the Command Senior Enlisted Leader for Marine Medium Tiltrotor Squadron 166, 3d Marine Aircraft Wing, Miramar, CA. In May 2020 VMM-166 (Rein) composited as an Aviation Combat Element attaching units from across 3d Marine Aircraft Wing and deployed to Ahmed Al Jaber Air Base, Kuwait under the control of the 13th Marine Expeditionary Unit. SgtMaj Kirkby served as the Command Senior Enlisted Leader for the Aviation Combat Element, Special Purpose Marine Air Ground Task Force-Crisis Response-Central Command 20.2.
From 8 June 2021 to 14 October 2022, SgtMaj Kirkby served as the Command Senior Enlisted Leader for Combat Instructor Battalion, The Basic School, Quantico, VA.
On 8 November 2022, SgtMaj Kirkby reported for duty as the Command Senior Enlisted Leader for 5th Marine Regiment in Camp Pendleton, CA. In March 2024, the Regiment composited as a Marine Air Ground Task Force attaching units from across I Marine Expeditionary Force and III Marine Expeditionary Force, and deployed to Darwin, Australia where SgtMaj Kirkby served as the Command Senior Enlisted Leader for Marine Rotational Force – Darwin, Marine Air Ground Task Force 24.3.
SgtMaj Kirkby was slated for his current billet and reported to 4th Marine Division on 4 April 2025.
Sergeant Major Kirkby's personal awards include the Meritorious Service Medal with two gold stars, Navy and Marine Corps Commendation medal with three gold stars, Navy and Marine Corps Achievement Medal with two gold stars.