He attended graduate studies in the International Relations curriculum at the Fletcher School of Law and Diplomacy, Tufts University, as part of the Admiral Arthur S. Moreau Scholarship Program.

Walsh graduated first in his class and received a Master of Arts in Law and Diplomacy degree, entered the Doctorate Program with distinction and subsequently received a PhD After designation as a Naval Aviator, Walsh began operational flying with the "Golden Dragons" of Attack Squadron 192, deployed to the Indian Ocean aboard the aircraft carrier USS America and was later selected by Commander, Light Attack Wing Pacific, as the Junior Officer/Tailhook Pilot of the Year.

Walsh commanded the "Gunslingers" of Strike-Fighter Squadron 105 for missions in support of Operations Southern Watch and Deny Flight from USS Dwight D. Eisenhower.

He commanded Carrier Air Wing 1 for deployment in support of Operation Southern Watch aboard USS John F. Kennedy.

Walsh was a Special Assistant to the Director of the Office of Management and Budget as a White House Fellow.