Colonel (Col) Sean Killeen was commissioned in the United States Marine Corps (USMC) in Mar 1994, where shortly thereafter, he began his career as a Logistics Officer.
From 1995-97, Lieutenant Killeen served as the Air Delivery Platoon Commander and Operations Officer, Beach and Terminal Operations Company, 3d Support Battalion, 3d Force Service Support Group, and the Landing Support Detachment Commander, MEU Service Support Group-31, 31st Marine Expeditionary Unit (MEU), III Marine Expeditionary Force (MEF) in Okinawa, Japan.
Promoted, Captain (Capt) Killeen was transferred to Marine Corps Combat Development Command (MCCDC) in Quantico, VA, where he served as a Capabilities Assessment Officer, Warfighting Development Integration Division from 1998-2000. Selected for school, Capt Killeen attended the Amphibious Warfare School (AWS) in Quantico, VA from 2000-01. Reassigned to Marine Wing Support Squadron (MWSS) 171, Marine Wing Support Group 17, 1st Marine Aircraft Wing (MAW), III MEF in Iwakuni, Japan, Capt Killeen served as the Squadron S4 Officer, the Airfield Operations Company Commander, and the Squadron S3 Officer from 2001-04; he was promoted to Major (Maj) during this tour.
Selected for school, Maj Killeen attended the Marine Corps Command and Staff College (C&SC) in Quantico, VA from 2004-05. Reassigned to Manpower and Reserve Affairs in Quantico, VA, Maj Killeen served as the Head, Systems Support Branch, Manpower Management Enlisted Assignments from 2005-08, where he developed and managed the Marine Corps’ enlisted staffing plan. In 2008, Maj Killeen was reassigned to the II MEF G4 in Camp Lejeune, NC where he deployed to Operation IRAQI FREEDOM (OIF) from Jan 2009-Jan 2010 as the Reception, Staging, Onward Movement Detachment Commander, II MEF (Forward), Multinational Forces-West, in Al Asad, Iraq and Camp Virginia, Kuwait, where he managed all Marine Corps deployments and redeployments into and out of the Iraqi theatre.
Upon return from OIF as a newly promoted Lieutenant Colonel (LtCol), LtCol Killeen served as the II MEF G4 Operations Officer from 2010-11. Reassigned to Total Force Structure Division, MCCDC in Quantico, VA as the Command Element (CE) Branch Head, LtCol Killeen managed all Marine Corps CE force Structure from 2011-12. Selected for command, LtCol Killeen assumed command of MWSS-274, Marine Aircraft Group (MAG) 29, 2nd MAW in Cherry Point, NC from Aug 2012 to Nov 2014. While in command, LtCol Killeen deployed the Squadron to Operation ENDURING FREEDOM (OEF) from Mar-Oct 2014, where they supported a MAG in combat operations, ran Camp Bastion airfield security operations, served as the Camp Dwyer Senior Airfield Authority, and closed down all MWSS operations in Afghanistan as the Marine Corps extricated itself from OEF. The Squadron’s actions over this period earned their selection as the 2014 Marine Corps Aviation Association, James E. Hatch, MWSS of the Year, Award winner.
Selected to school, LtCol Killeen attended the US Naval War College (NWC) in Newport, RI from 2015-16, graduating with distinction.
Reassigned to Headquarters, Supreme Allied Command Transformation, North Atlantic Treaty Organization (NATO) in Norfolk, VA, Col Killeen served as the Head, Training and Exercises Branch, Joint Force Trainer from 2016-18 where he managed NATO’s Major Joint Exercise program, and coordinated and synchronized NATO’s entire exercise portfolio with the 29 Allied nations, partner nations, and other NATO stakeholders. In May 2018, Col Killeen assumed his current post as the Commanding Officer, Headquarters and Service Battalion, Marine Corps Recruit Depot, Parris Island.
Col Killeen is a graduate of the USMC AWS, USMC C&SC, and a distinguished graduate of the US NWC. His civilian education includes a BA in Criminal Justice from Glassboro State College, NJ, an MS in Information Telecommunications Systems Management (with honors) from Capitol College, MD, and an MA in National Security and Strategic Studies (distinguished graduate) from the US NWC, Newport, RI.
Col Killeen’s personal decorations include a Meritorious Service Medal (4th Award), a Navy and Marine Corps Commendation Medal (3rd Award), and a Navy and Marine Corps Achievement Medal.
He is married to wife, Lisa, and has two daughters.