U.S. Air Force photo by Airman First Class Ryan Conroy
On Sept. 21, 2014, Tech. Sgt. Matthew J. Greiner was engaged in an operation in Helmand, Afghanistan, when his team was ambushed by insurgents. Sustaining serious head injuries from a grenade, Greiner continued to provide air support, protecting his team for nearly 40 minutes and neutralizing the enemy threat.