Gregory enlisted in the U.S. Army and on 3 October 2009 was serving as a Specialist with Troop B, 3rd Squadron, 61st Cavalry Regiment, Task Force Destroyer, in Kamdesh District, Nuristan Province, Afghanistan, in support of Operation Enduring Freedom.

On that day, then-SPC Gregory's actions in the defense of Combat Outpost Keating, helped prevent it from falling into the hands of a Taliban force of more than 400 fighters.

Medals, Awards and Badges

Army Commendation Medal with Valor Device
Army Commendation Medal (3 Awards)
Army Achievement Medal (7 Awards)
Army Good Conduct Medal (2 Awards)
National Defense Service Medal
Afghanistan Campaign Medal with Campaign Star
Global War on Terrorism Service Medal
Korean Defense Service Medal
Army Service Ribbon
Overseas Service Ribbon (3 Awards)
NATO Medal
Certificate Of Achievement
Valorous Unit Award
Combat Action Badge