A native of Bakersfield, California Colonel McCullar enlisted in the Marine Corps Reserve in March of 1990. After completion of Recruit Training at Marine Corps Recruit Training Depot in San Diego, California and Marine Combat Training he reported to Hawk Missile School in Fort Bliss, Texas where he graduated as a Hawk Missile Technician. His enlisted service included duty with 4th Light Anti-Aircraft Missile Battalion in Fresno, California. Colonel McCullar was commissioned a Second Lieutenant in 1997 through the Platoon Leaders Course Program after graduation from California State University Bakersfield. Following graduation from The Basic School and Combat Engineer Officers Course, Colonel McCullar was assigned to 1st Combat Engineer Battalion, 1st Marine Division in Camp Pendleton, California from 1998-2001 where he served as the Utilities Platoon Commander for Engineer Support Company, Platoon Commander and Executive Officer for Bravo Company, and the Commanding Officer of Alpha Company.
In June 2001 Colonel McCullar reported to 3d Marine Division in Okinawa, Japan where he served as the Division G-3 Training Officer and the Assistant Operations Officer for the 4th Marine Regiment. Subsequently, Colonel McCullar was assigned as the Commanding Officer of Combat Engineer Company, Combat Assault Battalion. Throughout this period, Colonel McCullar participated in numerous theater security cooperation exercises throughout Asia including: Japan, Korea, the Philippines and Thailand.
In June of 2004, Colonel McCullar reported for duty with the Marine Corps Engineer School at Camp Lejeune, North Carolina as the Academics Officer and Class Advisor for Combat Engineer Instruction Company. In December of 2005, Colonel McCullar was assigned as an individual augment to I Marine Expeditionary Force where he served on a Military Transition Team as the Engineer Advisor for the 7th Iraqi Army Division in Ramadi, Iraq. In January 2007, Colonel McCullar returned to the Marine Corps Engineer School and was assigned as a curriculum developer for the Explosive Hazards Branch.
In June of 2007, Colonel McCullar executed orders to 8th Engineer Support Battalion, 2d Marine Logistics Group. During this tour of duty, Colonel McCullar served as the Commanding Officer of Engineer Support Company in Support of 6th Engineer Support Battalion (FWD) in Anbar Province, Iraq as well as the Battalion Operations Officer and Executive Officer of 8th Engineer Support Battalion in Helmand Province, Afghanistan.
From July 2010 to June 2011, Colonel McCullar attended Army Command and General Staff College at Fort Leavenworth, Kansas where he also graduated from Kansas State University with a Master of Science Degree in Adult and Continuing Education. Upon Graduation, Colonel McCullar was assigned as the Operations Officer for Marine Corps Logistics Operations Group at Camp Johnson, North Carolina from July 2011 to July 2012. Colonel McCullar then executed orders to Marine Corps Engineer School where he served as the Executive Officer from July 2012-July 2014.
Colonel McCullar reported to 2d Marine Division in July 2014 where he was temporarily assigned to the Division G-3 prior to taking command of 2d Combat Engineer Battalion in December 2014. Colonel McCullar relinquished command of 2d Combat Engineer Battalion in January of 2017 and was subsequently assigned as the Operations Officer of Task Force Southwest where he deployed to Helmand Province, Afghanistan from April 2017 to January 2018. Upon return from Afghanistan, he was assigned as the Executive Officer of 6th Marine Regiment until June 2018. Colonel McCullar subsequently attended Air War College at Maxwell Air force Base, Alabama where he received a Master of Science Degree in Strategic Leadership. In 2019, he reported to Marine Corps Installations East where he served as the AC/S G-3/5.
His personal decorations include the Bronze Star, Meritorious Service Medal with three gold stars, Navy Commendation Medal with three gold stars and the Combat Action Ribbon.