Capt McCormack enlisted in the Marine Corps in July of 1999 and completed recruit training at MCRD San Diego. Following recruit training, PFC McCormack attended Marine Combat Training at SOI West and Marine Corps Engineer School.

  Lance Corporal McCormack served with III MEF HQ Group in Okinawa, Japan from May 2000 to June 2001 and reported to MWSS-372 aboard Camp Pendleton in July of 2001. From March to June 2003, Corporal McCormack deployed to Iraq in support of Operation IRAQI FREEDOM (OIF-1). In September 2003, Corporal McCormack reported to MACS-24 in Virginia Beach, Virginia for service as the Engineer Section NCOIC.

  In 2006, Sergeant McCormack was accepted into the Broadened Opportunity for Officer Selection Training program. Upon graduation in June 2007, he was transferred into the Marine Enlisted Commissioning Education Program at the University of South Carolina. In May 2009, Sergeant McCormack received his commission as a Second Lieutenant and was transferred to The Basic School, Quantico, Virginia. Upon completion of The Basic School and Infantry Officer Course, 2ndLt McCormack reported to V11 for duty as a Rifle Platoon Commander.

  While assigned to Alpha Company V11, 2ndLt McCormack served as the Maritime Raid Force Infantry Platoon Commander for the 13th MEU from October 2010 through September 2011 where he conducted VBSS and counter-piracy operations. As a Weapons Company CAAT Platoon Commander in 2012, he deployed to Afghanistan in support of Operation ENDURING FREEDOM where his platoon fought in the Trek Nawa region of Nawa Province. 

  In February 2013 Captain McCormack was transferred to First Recruit Training Battalion, MCRD Parris Island, South Carolina where he served as a Series Commander, Company Commander, and as the 1st Recruit Training Battalion Executive Officer. In July of 2016 he reported to Expeditionary Warfare School (EWS) in Quantico, Va. Completing EWS as a Distinguished Graduate, Captain McCormack reported to V14 in May of 2017 and was assigned as the 1st Marines Regimental Surveillance and Target Acquisition (RSTAC) Company Commander. In December of 2017, he assumed command of Weapons Company V14, the billet he currently holds.

Personal Awards Include: MSM, NAM (X3) with Valor Device, and CAR (X2)