Sergeant Major Aric Lonchar enlisted in the United States Marine Corps in June 2008 in West Liberty, Kentucky. He reported to Marine Corps Recruit Depot Parris Island on 15 June 2008 and graduated with Mike Company, 3rd Recruit Training Battalion, on 12 September 2008. He completed Marine Combat Training at Camp Geiger with India Company before reporting to the Marine Corps Communications-Electronics School in Twentynine Palms, California, for Basic Radio Operator training.
In January 2009, Sergeant Major Lonchar reported to 3rd Battalion, 4th Marines, 1st Marine Division, serving as a Field Radio Operator with Headquarters and Service Company, Communications Platoon. He deployed twice to Helmand Province, Afghanistan, in support of Operation Enduring Freedom.
In December 2011, he received orders to Drill Instructor School, Marine Corps Recruit Depot San Diego, graduating with Class 4-12 on 19 September 2012. He served with 2nd Recruit Training Battalion as a Drill Instructor for Hotel Company and later as a Senior Drill Instructor for Fox Company. During this tour, he earned multiple impact achievements and a meritorious promotion to Staff Sergeant on 2 July 2015.
In November 2015, Sergeant Major Lonchar reported to Marine Wing Communications Squadron 28, Marine Air Control Group 28, II Marine Aircraft Wing, where he served as the Transmission Platoon Staff Noncommissioned Officer in Charge for Bravo Company. From May 2016 to August 2016, he served as Officer Candidate School, Quantico, Virginia, as a Sergeant Instructor.
In April 2017, Sergeant Major Lonchar was assigned to the Georgian Liaison Team, Rotation 7, supporting the Georgian Deployment Program, Resolute Support Mission. He deployed to the Republic of Georgia in November 2017 as a Foreign Advisor to the 11th Georgian Light Infantry Battalion (GLIB). In April 2018, he redeployed with the battalion to Bagram, Afghanistan, where he served as a Foreign Military Advisor while supporting Task Force Manchu, U.S. Army, 4th Battalion, 9th Infantry Regiment.
In October 2019, Sergeant Major Lonchar reported to Marine Corps Embassy Security Guard Detachment Commander School in Quantico, Virginia, where he graduated as the recipient of the Leadership Award before assuming command of Marine Security Guard Detachment Riga, Latvia.
In April 2021, Sergeant Major Lonchar reported to the Marine Corps Embassy Security Group Training Center as an Instructor/Advisor. He was recognized as the Instructor Advisor of the Year and later served as the Senior Noncommissioned Officer in Charge and Chief Instructor of the Marine Security Guard School. He was promoted to First Sergeant in May 2023 and assumed duties as the Command Senior Enlisted Leader for Marine Corps Embassy Security Group Region 1, Eastern Europe and Eurasia.
In March 2025, Sergeant Major Lonchar was selected by the Sergeant Major of the Marine Corps to attend the United States Army Sergeants Major Academy, the Department of War's premier senior enlisted leadership education program. While attending the Academy, he earned a Master of Science in Organizational Leadership from Excelsior University, graduating with a 4.0 grade point average. In June 2026, he graduated from the United States Army Sergeants Major Academy, Class 76, earning the Superior Academic Achievement Award in recognition of his exceptional academic performance. He was subsequently promoted to Sergeant Major and assigned as the Command Senior Enlisted Leader for Marine Medium Tiltrotor Squadron 363, Marine Aircraft Group 24, 1st Marine Aircraft Wing, aboard Marine Corps Base Hawaii.
Sergeant Major Lonchar's personal decorations include the Meritorious Service Medal, Navy and Marine Corps Commendation Medal (with "C" device and Gold Star in lieu of third award), the Navy and Marine Corps Achievement Medal (Gold Star in lieu of fourth award) and the Combat Action Ribbon.