Lieutenant Colonel Thomas James Duff graduated from the United States Naval Academy and was commissioned a Second Lieutenant in the United States Marine Corps in 2004.  Upon completion of The Basic School, he reported to Flight School in Pensacola, Florida and was designated a Naval Aviator in August 2006.

First Lieutenant Duff reported to Marine Aircraft Group (MAG) 39 for initial training in the AH-1W at Marine Light Attack Helicopter Training Squadron (HMLAT) 303. In February 2007, he reported to Marine Light Attack Helicopter Squadron (HMLA) 169.  Between 2007 and 2009, he deployed with the Vipers to Al Anbar Province in support of Operation Iraqi Freedom and to Helmand Province in support of Operation Enduring Freedom.  During this period he served as a Schedule Writer and Flightline Officer-in-Charge.

In March 2010, Captain Duff attended the Weapons and Tactics Instructor Course.  In August 2010, he attended the Aviation Safety Officer Course.  Captain Duff deployed a third time with HMLA-169 to Helmand Province, Afghanistan in support of Operation Enduring Freedom as the Squadron Aviation Safety Officer and AH-1Z Standardization Officer.

In June 2012, Captain Duff reported to Marine Aviation Weapons and Tactics Squadron One (MAWTS-1) to serve as an AH-1 Instructor Pilot.  He attended the Tactical Air Control Party Course in August 2012 and assumed the billet of Forward Air Controller (Airborne) and Fires Subject Matter Expert.  During his second year at MAWTS-1, Captain Duff served as the Squadron Aviation Safety Officer and advanced the Tactical Risk Management concept.  In his third year, Captain Duff served in the Aviation Development, Tactics, and Evaluation Department as the Tactical Reconnaissance and Unmanned Aerial Systems Specialist while continuing his primary role as an AH-1 Instructor Pilot.

In 2015, Major Duff was selected to attend the Naval War College in Newport, Rhode Island for the College of Naval Command and Staff.  While there, Major Duff participated in the Naval Staff College (NSC) International Program as one of six U.S. Officers embedded into a group of 72 International Officers from 53 different countries.  During this time, Major Duff traveled the country with the NSC, earned a Master’s Degree in Defense and Strategic Studies, and graduated with distinction. 

In July 2016, Major Duff reported to MAG-39 and joined the HMLA-369 Gunfighters.  As the Aircraft Maintenance Officer, he led the Squadron’s Maintenance Department through the Commander, Naval Air Forces Inspection in support of their upcoming deployment to Okinawa, Japan.  In November 2017, Major Duff deployed in support of the Unit Deployment Program and assumed the billet of Executive Officer until his departure from the unit. 

In February 2019, Major Duff reported to Headquarters, Marine Corps Aviation to serve as the Attack and Utility Helicopter Coordinator for the Deputy Commandant for Aviation.  As the H-1 Subject Matter Expert, Major Duff worked closely with the Fleet Marine Force, Naval Air Systems Command, other government agencies, and industry partners to coordinate all aspects of H-1 requirements, resources, and capability acquisition. 

In July 2021, Lieutenant Colonel Duff reported to MAG-39.  He assumes command of the HMLA-169 Vipers in January 2022.