Surveillance video shows the gunman, 25-year-old Mostafa Hendi, walking into the We Buy Gold store in Hendersonville, N.C.
The store employee, Derek Mothershead, said Hendi came in demanding money, so he handed him the loot, then threw a quick left hook to the face to knock him out cold.
"If he wants money, get a job. Work like everybody else in this world," Mothershead said. "I was scared about the gun. When I made my mind up, I said I got to hit him with everything I've got."
Mothershead helped stop Hendi's bleeding while waiting for police to arrive.