Alexandra Godlund of the Nacka police said a Stockholm parent was backing the Volkswagen Passat out of a Stockholm driveway Sunday evening when the boy got caught beneath it, Swedish news agency TT reported Monday.
Emergency services were contacted, but the first helper on the scene was an unidentified man who helped the parent lift the back of the car and free the youngster.
"Yes, from what has been reported, it seems to have been a strong neighbor, unknown to us, but a man by all accounts, who with the help of a parent managed to lift up the car's rear end," Godlund told the Dagens Nyheter newspaper. "When our patrol arrived on the scene, the man had already got the boy loose."
The boy did not suffer any serious injuries, but was air-lifted to a hospital as a precaution.
Godlund praised the boy's unidentified rescuer.
"This is really fantastic, it was a true hero's tale. With an unknown hero," Godlund said.