First Sergeant Ketner is a native of Nashville, Tennessee, and enlisted in the Marine Corps in August of 2003. He attended recruit training at Marine Corps Recruit Depot, Paris Island, South Carolina. In November of 2003 he attended the School of Infantry and Machine Gunners Course at Camp Geiger, North Carolina where he received the MOS of 0331, Infantry Machine Gunner.
In January 2004, First Sergeant Ketner reported to Company I, 3d Battalion 24th Marines, Nashville Tennessee. He served as a Machine Gunner with the Company to Fallujah, Iraq in support of Operation Iraqi Freedom II in 2004. He was meritoriously promoted to Lance Corporal while forward deployed.
From November 2004 to September 2009, First Sergeant Ketner served in the Reserves with Company I, 3d Battalion 24th Marines. He served initially as a Machine Gunner and worked his way to Platoon Sergeant. During this period of time he attended Corporals Course and Advanced Infantryman Squad Leaders Course. In January of 2007 he was promoted to Corporal and in November of 2007 he was meritoriously promoted to the rank of Sergeant.
In November 2009, First Sergeant Ketner was deployed in support of Operation Iraqi Freedom IX where he served in the billets of Platoon Sergeant and NCOIC for the Regional Detention Facility, Al Asad Iraq.
In December of 2010, First Sergeant Ketner returned to the Reserves with Company I, 3d Battalion 24th Marines where he served as a Platoon Sergeant until August 2012. He was promoted to Staff Sergeant in February 2011. In 2011 he served as the SNOIC for Excercise Trade Winds, conducted in the Caribbean region.
In August 2012, First Sergeant Ketner attached to Headquarters, 4th Reconnaissance Battalion, deploying with the Special Purpose Marine Air-Ground Task Force, Black Sea Rotational Force 12. Where he filled the Team Leader billet for one of the small team security-cooperation groups.
From July 2013 to August 2020, First Sergeant Ketner served with Company K, 3d Battalion 23d Marines where he served in the billets of Platoon Sergeant and Company Gunnery Sergeant. He was promoted Gunnery Sergeant in June of 2018. He attended Career Course and Advance Course in Quantico, Virginia. In 2017 he served as the SNOIC for Exercise Sea Breeze, conducted in Ukraine.
From September 2020 to May 2022, First Sergeant Ketner served with Company I, 3d Battalion 23d Marines where he served as the Company Gunnery Sergeant.
In May of 2022 First Sergeant Ketner was promoted to his current rank and reported for duty with 4th Combat Engineer Battalion for assignment as Alpha Company First Sergeant where he served until December 2024. In January 2025 he reported to Battery M, 3rd Battalion 14th Marines for his second assignment as Company First Sergeant where he is currently serving.
First Sergeant Ketner's personal awards include the Navy and Marine Corps Commendation Medal with 1 Gold Star, the Navy and Marine Corps Achievement Medal with 3 Gold Stars, and the Army Achievement Medal. First Sergeant Ketner completed his Bachelor of Science from Bethel University, in 2016.