Rear Admiral Thornton is a native of Pacifica, Calif. where he began his maritime career as a U.S. Naval Sea Cadet. He graduated Boot Camp as Navy League’s Outstanding Recruit in San Diego before completing Hospital Corpsmen “A” School at Balboa Naval Hospital. His first duty assignment was Naval Branch Clinic, Marine Corps Recruit Depot, San Diego. He then volunteered and graduated from Basic Underwater Demolition/SEAL training and reported to SEAL Team 5. He then transitioned to the Navy Reserve assigned to NR Naval Special Warfare Unit 1, then Special Boat Unit 11.

Thornton earned an Associate of Science in Chemistry from the College of San Mateo, a Bachelor of Science with majors in biochemistry and entomology from the University of California, Davis, and a Doctor of Medicine from St George’s University School of Medicine. He completed residency in internal medicine at Seton Hall University and Fellowship in Pulmonary & Critical Care Medicine at the University of California, Davis. He is triple board-certified by the American Board of Internal Medicine: Internal Medicine, Pulmonary Disease, & Critical Care Medicine. Additionally, he is a graduate of Marine Corps University’s Command and Staff College Distance Education, Cornerstone: The Commandant’s Combined Commandership Course, and the Joint Forces Staff College Joint and Combined Warfighting School where he was the recipient of the Reserve Officer’s Association Distinguished Writing Award.

Thornton received a direct commission in the Medical Corps, re-affiliating with the Navy Reserve in 2004 and assigned to 2nd Battalion, 23d Marines as Assistant Battalion Surgeon. Since then, he’s completed various fleet, operational, and staff assignments including Naval Special Warfare Group 11’s Operational Support Team 1 & SEAL Team 17; Operational Health Support Unit Camp Pendleton; 23d Marine Regiment; NR Commander, U.S. 7th Fleet; and Executive Officer, 4th Medical Battalion. In addition, he was selected for a USSOUTHCOM sponsored exchange with Marinha do Brasil’s Riverine Force serving aboard NAsH Doutor Montenegro (U16) Manaus, Brazil.

Thornton’s mobilizations include officer-in-charge, Regional Detention Facility’s Health Clinic, Multi-National Forces West, Ramadi, Iraq; assistant task force surgeon, Task Force Military Police 3/14, I MEF (fwd), Operation Iraqi Freedom; and commanding officer, Expeditionary Medical Facility Camp Pendleton leading a full-unit mobilization providing Role 3 capabilities to U.S. 7th Fleet and U.S. Naval Forces Marianas in support of the USINDOPACOM COVID-19 outbreak response. He completed a sequential major command as force surgeon, U.S. Naval Forces Korea before assuming duties as Director, Reserve Component, OPNAV 0931 and Chief, Reserve Medical Corps October 1, 2025.

Rear Admiral Thornton is authorized to wear the Special Warfare (SEAL), Naval Parachutist, Fleet Marine Force Officer, and Command Ashore breast insignias. He is the recipient of various military decorations, campaign and service awards, and has had the distinct honor of serving on Navy teams awarded the Navy Unit Commendation, Meritorious Unit Commendation, and Republic of Korea Presidential Unit Citation.

In his civilian career, Thornton is a senior partner/specialist with The Permanente Medical Group and holds various leadership positions within the Kaiser-Permanente enterprise.

Last Updated: 16 October 2025