Colonel Jim Fallon is a native of Massachusetts, received a Bachelor of Arts degree from Norwich University and was commissioned in August 1992. After completing The Basic School and Infantry Officers' Course, he was assigned to 3rd Battalion, 7th Marines where he served as Rifle Platoon Commander, Company K and Anti Armor Platoon Commander, Weapons Company.

In 1996, Colonel Fallon reported for duty as a Company Officer, Naval Academy Preparatory School. In 1999, he received orders to Amphibious Warfare School.

In July 2000, Colonel Fallon reported to 1st Battalion, 1st Marines where he served as Company Commander for Company C, deploying with the 15th Marine Expeditionary Unit in support of Operation Enduring Freedom. In 2002, he deployed as the Operations Officer for Battalion Landing Team 1/1, with the 13th Marine Expeditionary Unit. He received orders to Marine Corps Command and Staff College graduating in June 2005.

In June 2005, Colonel Fallon reported to Special Operations Command Central completing assignments in both the J5 and J3 and deployed in support of Operation Iraqi Freedom.

In July 2008, he received orders to serve as the Executive Officer of Regimental Combat Team 1 and deployed in support of Operation Iraqi Freedom. In 2009, Colonel Fallon was reassigned as the Operations Officer for 1st Marine Regiment and deployed in support of Operation Enduring Freedom as Regimental Combat Team 1.

Colonel Fallon reported to Marine Forces Central Command for duty as Chief of Operations in 2011 and assumed Command of Infantry Training Battalion-West in 2012. In 2014 he was assigned as the Executive Officer of the 15th Marine Expeditionary Unit, completed one deployment and was transferred to I Marine Expeditionary Force G3 serving as the G37 and Deputy G3 while simultaneously serving as the Marine Expeditionary Brigade Chief of Staff.