Lieutenant Colonel Costello was commissioned through the Platoon Leaders Class Program after graduation from Virginia Tech in 2000. Following completion of The Basic School (TBS) in Quantico Virginia, he reported to Naval Air Station Pensacola, Florida, for flight training and was designated a Naval Aviator in May 2003. Subsequently, First Lieutenant Costello reported to Marine Medium Helicopter Training Squadron 164, aboard Camp Pendleton, California, for training in the CH-46E.

In March 2004, First Lieutenant Costello reported to Marine Medium Helicopter Squadron 264 (HMM-264) aboard Marine Corps Air Station (MCAS) New River where he served for 5 years. During this period, he deployed in support of Operation IRAQI FREEDOM (OIF 04-06) and twice with the 26th Marine Expeditionary Unit to the Central Command (CENTCOM) area-of-responsibility. His flight designations included Night Systems Instructor (NSI) and Assault Flight Leader (AFL). His billets included Airframes Division Officer, Aviation Safety Officer and Director of Safety and Standardization.

In June 2009, Captain Costello was transferred to MATSG-21 in Pensacola, Florida, where he served as an advanced helicopter flight instructor. While there, he served as the Senior Marine, Safety Department Head, and standardization pilot for Contact, Tactics, and Instrument flight.

In July 2012, Major Costello reported to Marine Air Group 39 (MAG-39) in Camp Pendleton, California, and received follow-on orders to Camp Leatherneck, Afghanistan, where he served as the Marine Central Command Liaison Officer and Planner for I MEF(FWD) in support of Operation ENDURING FREEDOM. When he returned in March 2013, he reported to HMM-268 for relocation to MAG-16, MCAS Miramar, and transition to the MV-22. He served as the Aircraft Maintenance Officer throughout the squadron’s transition to VMM-268 and then deployed as the squadron’s Executive Officer with SPMAGTF-CR-CC 16.1, in support of Operation INHERENT RESOLVE.

In July 2016, Major Costello reported to United States Special Operations Command (USSOCOM) in Tampa, Florida for Joint Duty as a capability analyst and to serve as the lead planner for the USMC-USSOCOM Warfighter Talks.

In 2019, Lieutenant Colonel Costello received orders back to MAG-26 in North Carolina to serve as the Commanding Officer of VMM-263.

Lieutenant Colonel Costello received his MS in Management from the University of Maryland University College and is a graduate of the Aviation Safety Officer Course, Aviation Maintenance Officer Course, Marine Corps Command and Staff Course, and the Joint and Combined Warfighting School.

Lieutenant Colonel Costello’s personal decorations include the Defense Meritorious Service Medal, Meritorious Service Medal, Air Medal with Strike Flight Numeral “6”, Joint Service Commendation Medal, Navy and Marine Corps Commendation Medal with 2 gold stars and the Navy and Marine Corps Achievement Medal.