Sergeant Major Kenneth L. Castille enlisted in the Marine Corps in November 1999. Upon completion of recruit training at Parris Island, South Carolina, he attended Marine Combat Training at Camp Geiger, North Carolina. In March of 2000, he attended the Basic Cannon Crewman Course at Fort Sill, Oklahoma, and was assigned the MOS of Cannon Crewman (0811).
    
In June of 2000 Private Castille was assigned to Echo Battery, 2nd Battalion, 10th Marines, 2D Marine Division, Camp Lejeune, North Carolina for duty as a Cannon Crewman.  He deployed with Battalion Landing Team (BLT) 2/8, 24th Marine Expeditionary Unit (MEU) in 2001. During this deployment, Lance Corporal Castille was meritoriously promoted to the rank of Corporal.                                    
    
In November 2002 he was promoted to Sergeant and in January 2003 he was reassigned to Alpha Battery, 1st Battalion, 10th Marines. Soon after checking in, he deployed with the battalion to Iraq with Regimental Combat Team Two as a Section Chief. His battalion conducted combat operations during the invasion within the area of An Nasiriyah, Iraq.
   
From January 2004 to January 2007, Sergeant Castille was assigned as a Combat Instructor at School of Infantry (SOI), East. During this tour he held the billets of Combat Instructor, Platoon Commander, Chief Combat Instructor, and Primary Instructor. Also during his tour he was meritoriously promoted to the rank of Staff Sergeant in July of 2006.
    
In February 2007 Staff Sergeant Castille checked back into Alpha Battery, 1st Battalion, 10th Marines. This time he held the billets of Section Chief, Local Security Chief, Guns Platoon Sergeant, and Battery Gunnery Sergeant. In 2008 Staff Sergeant Castille deployed to Afghanistan as the Local Security Chief with BLT 1/6, 24th MEU. During this deployment his unit conducted combat operations in the city of Garmsir within the Southern Helmand providence in support of Operation Asade Wosa.
    
In July of 2009 he transferred to Bravo Battery, 1st Battalion, 12th Marines, 3D Marine Division, MCBH. Staff Sergeant Castille deployed as the Guns Platoon Sergeant and Local Security Chief in support of the Unit Deploying Program to Okinawa, Japan. He was then promoted to Gunnery Sergeant in September 2011 and officially assumed the duties as the Battery Gunnery Sergeant of Bravo Battery. In March 2011 Gunnery Sergeant Castille deployed once again to Okinawa, Japan in support of the Unit Deploying Program.
    
In June 2013 Gunnery Sergeant Castille checked into Alpha Battery, 1st Battalion, 10th Marines as the Battery Gunnery Sergeant. He was moved six months later to Bravo Battery and deployed with BLT 1/6, 22nd MEU.

In February of 2015 Gunnery Sergeant Castille was promoted to First Sergeant and deployed with Echo Company 2nd Battalion, 6th Marines, BLT 2/6, 26th MEU. Upon returning he moved to Headquarters Company, 6th Marine Regiment. From March 2017 to January 2018, First Sergeant Castille filled the Force Generation Elements’ Sergeant Major billet for 6th Marines while the regiment was forward deployed with Task Force Southwest.

In February 2018, First Sergeant Castillle moved cross country to Headquarters Company, 1st Law Enforcement Battalion aboard Camp Pendleton, Ca. He was then selected to the rank of Sergeant Major and executed orders to Marine Tactical Air Command Squadron (MTACS) - 38 in October 2019 where he is currently serving as the Squadron Sergeant Major.