Major Walsh grew up in Plantation, Florida, and graduated from Florida State University in 2007. Following graduation, he attended Officer Candidates School and was commissioned a Second Lieutenant in the Marine Corps. He subsequently attended The Basic School; served temporarily at the Marine Corps Network Operations and Security Center; and then completed Basic Communications Officer Course in 2008, graduating on the Commanding General’s Honor Roll.
In January 2009, he reported as the S-6 and Communications Platoon Commander, Headquarters Company, 3d Low Altitude Air Defense Battalion (3d LAAD Bn) at Camp Pendleton, California. While at 3d LAAD Bn, he deployed in support of Operation Enduring Freedom as the S-6 and Information Operations Officer.
Major Walsh transferred to Okinawa, Japan, in 2011. There he served as the Commanding Officer, Headquarters Company, Combat Assault Battalion; S-6, 4th Marine Regiment; and Deputy Operations Officer, G-6, III Marine Expeditionary Force where he also supported OPERATION DAMAYAN as the Joint Network Control Center Operations Officer.
In 2014, Major Walsh left the Fleet Marine Forces to serve as the Deputy G-6, Marine Corps Installations – National Capital Region, Quantico, VA. While at Quantico, he augmented the Winter 2016 Officer Candidates School, Officer Candidate Class-221 as Staff Platoon Commander, First Platoon, Charlie Company.
From 2017 to 2020, Major Walsh served with 1st Marine Raider Support Battalion, Marine Raider Support Group, Marine Corps Special Operations Command (MARSOC) as Company Commander, Headquarters Company and Company Commander, Communications Company. While assigned to MARSOC, Major Walsh deployed in support of Operation Freedom's Sentinel and Operation Resolute Support serving as the Information Management Officer, J-3, NATO Special Operation Combatant Command/Special Operations Joint Task Force – Afghanistan. Major Walsh subsequently attended Marine Corps Command and Staff College in 2020 – 2021, graduating as a distinguished graduate and a Gray Scholar.
Major Walsh has a Bachelor of Arts in Political Science, a Master’s in Military Studies, and a Master's in Information Technology. He is a graduate of Command and Staff College, Expeditionary Warfare School non-resident, SERE "C," Weapons and Tactics Instructor School, Joint Special Operations Planning Course, and maintains a Security+ CE certification.
Major Walsh's personal awards include the Defense Meritorious Service Medal, Joint Service Commendation Medal w/"C" device, Navy and Marine Corps Commendation Medal (4), and the Joint Service Achievement Medal.