Lieutenant Colonel Sumption was born in Woodbridge, England and graduated from the United States Naval Academy in 2006.  Second Lieutenant Sumption was designated an aviation intelligence officer and completed The Basic School and Aviation Intelligence Officer's Course in 2008.   In May 2008 1st Lieutenant Sumption received orders to Marine Air Group-16 with follow-on assignment to HMM-166, MCAS Miramar, CA.  HMM-166 composited as the Aviation Command Element to the 11th Marine Expeditionary Unit and completed workups for a 2009-2010 WESTPAC deployment.  During this time, he completed Weapons and Tactics Instructor Course (WTI) at the Marine Aviation Weapons and Tactics Squadron-1 (MAWTS-1), as well as Personnel Recovery Plans and Operations (PR-301) through the Joint Personnel Recovery Education and Training Center.  In 2010 1st Lieutenant Sumption reported back to MAG-16, was promoted to Captain and deployed with I MEF Command Element to Operation Enduring Freedom as the Foreign Disclosure Officer for RC(SW) from 2010-2011.    In June 2011 Captain Sumption received orders to Marine Detachment (MARDET), Dam Neck, VA as an instructor for the MAGTF Intelligence Officer's Course (MIOC).  While assigned to the MARDET, Captain Sumption completed Basic and Senior Instructor certifications as well as curriculum developer course through TECOM.  He also completed several courses as part of the Defense Intelligence Strategic Analyst Program (DISAP).  From 2012 to 2014 he was designated as the course director for MIOC.    From June 2014 until April 2015, Captain Sumption served as the S-2, Senior Intelligence Officer for 8th Marine Regiment.  During that time the Regiment facilitated several Marine Corps Combat Evaluation Exercises for subordinate battalions as well as the 6th Marine Regiment Special MAGTF Crisis Response Certification.  In April 2015 Captain Sumption reported to 3d Battalion, 8th Marine Regiment as the S-2, Senior Intelligence Officer.  He deployed with 3/8 as the Black Sea Rotational Force 15-2 from 2015 to 2016 in Mihail Kogălniceanu Airbase, Romania.  From July 2016 to July 2017 Major Sumption served as the 2d Marine Logistics Group G-2.  During this time, he also completed the Intermediate MAGTF Logistics Operations Course (IMLOC 1-17) in 2017.   Major Sumption reported to 1st Marine Aircraft Wing, Okinawa, Japan in July 2017 for duty as the G-2 Operations Officer, and then Deputy Assistant Chief of Staff G-2.  In 2018 he deployed for training with1st Marine Aircraft Wing in support of Ulchi Freedom Guardian 18 in the Republic of Korea.  From 2019 to July 2020, Major Sumption served as the Aide-de-camp Commanding General, III Marine Expeditionary Force.   Major Sumption reported to the ISR Section within within Intelligence Division, Deputy Commandant for Information, HQMC in July 2020 until he was selected for promotion to lieutenant colonel and was reassigned as the Operations Officer for the Intelligence Division in April 2021.   Lieutenant Colonel Sumption reported to the Marine Corps Tactics and Operations Group (MCTOG) at MCAGCC, 29 Palms, CA in July 2023 where he assumed his current billet as the MCTOG Executive Officer.   His personal decorations include the Meritorious Service Medal with gold star in lieu of second award, Navy and Marine Corps Commendation Medal with gold star in lieu of second award, and the Navy and Marine Corps Achievement Medal.