Sergeant Major Nathan D. Aja enlisted in the Marine Corps in January 2003 from Marine Corps Recruit Depot San Diego, CA. After recruit training, Private First Class Aja attended the School of Infantry at Camp Pendleton and received the Military Occupational Specialty of 0311, Infantry Rifleman. Upon completion, he reported to 2nd Battalion, 3d Marines aboard Marine Corps Base Hawaii.
Promoted to Lance Corporal in October 2003, he then deployed the following November on the 31st Marine Expeditionary Unit. During the workup for his second deployment in March of 2005, he was promoted to Corporal. From June 2005 until January 2006, he deployed to the Kunar Province of Afghanistan in support of Operation Enduring Freedom (OEF) as a team leader.
On 1 October 2006, he was promoted to the rank of Sergeant and, in January 2007, reached the end of his active service where he transferred to the Individual Ready Reserve (IRR). While in the IRR, Sergeant Aja attended Windward Community College on the island of Oahu, completing 12 college credit hours toward his general education.
In May 2007, Sergeant Aja reenlisted to active duty and reported to 2nd Battalion, 3rd Marines, Golf Company as a Squad Leader. From February to August 2008, Sergeant Aja served as a Mounted Section leader for the Company Commander's Personal Security Detachment while in support of Operation Iraqi Freedom for his third deployment. May of 2009 was his fourth deployment, this time to the Helmand Province, Afghanistan as a Squad Leader for another tour in support of OEF.
In July 2010, Sergeant Aja was assigned to SOI West Detachment Hawaii and served as a Squad Instructor for the Infantry Squad Leaders Course. Then after earning the Military Occupational Specialty 0917, he then served as the Chief Instructor for all Martial Arts Instructor Courses for SOI West Detachment Hawaii.
Sergeant Aja was promoted to Staff Sergeant on 1 January 2012, and then on 1 August 2012, reported to 3d Battalion, 7th Marines. Staff Sergeant Aja served as a Platoon Sergeant with Kilo Company for his fifth and sixth deployments. First to OEF (Helmand Province) then to Operation Inherent Resolve aboard Al Asad Air Base in Iraq.
Upon his return from Operation Inherent Resolve, Staff Sergeant Aja received orders to 3d Battalion, 3d Marines, reporting in April of 2016. On arrival, he was assigned to Lima Company as a Platoon Sergeant and would deploy in June 2016 to Okinawa for his seventh deployment. Staff Sergeant Aja was then promoted to Gunnery Sergeant on 1 July 2017. Serving as the Company Gunnery Sergeant he deployed to Okinawa for his eighth deployment in November 2017. In July 2018, Gunnery Sergeant Aja reported to Marine Security Guard School to become a Detachment Commander. From October 2018 to July 2021, he was posted at the U.S. Embassy in Bishkek, Kyrgyzstan, and the U.S. Embassy in Panama City, Panama.
After another successful Special Duty Assignment tour, Gunnery Sergeant Aja was promoted to First Sergeant on 13 July 2021, reporting to 3d Battalion, 11th Marines. In November 2021, he deployed on the 31st Marine Expeditionary Unit as a part of the Battalion Landing Team, 1st Battalion, 5th Marines, where he served as the Battery K First Sergeant on his ninth deployment.
In December 2022 First Sergeant Aja received orders to Marine Corps Communication Electronics School (MCCES), serving as the Communications Training Battalion Command Senior Enlisted Advisor and the MCCES Headquarters Company Unit Senior Enlisted Leader. First Sergeant Aja was promoted to Sergeant Major on 1 March 2024 and received orders to assume the role of Battalion Sergeant Major for 3d Battalion, 4th Marines on March 8th, 2024. While serving as the Battalion Sergeant Major he executed a tenth and eleventh deployment, first to Okinawa Japan for UDP-West 25.1, followed by JTF- Southern Border 26.1. On 20 March 2026 Sergeant Major Aja was appointed as the Sergeant Major of Marine Wing Headquarters Squadron 3.
Sergeant Major Aja has a bachelor's degree from American Military University in Business Management, his personal decorations include the Meritorious Service Medal, Navy Commendation Medal with 2 gold stars, Navy and Marine Corps Achievement Medal with Combat “V” and five gold stars and the Combat Action Ribbon.