The car jumped the curb and struck the front of Pizza, Bagel, Burger around 3:30 p.m.
Witnesses say the car drove into the restaurant off Avenue I.
It went about a quarter of the way inside the restaurant, they said.
At least two of the injured may be teenagers.
Five people were transported to area hospitals. Two went to Lutheran Medical Center, one in critical condition. Three adults, all in stable condition, were taken to Maimonides Medical Center.
Officials said a sixth person was injured, but refused medical attention at the scene.
FDNY EMS treated one person at the scene who they said was not seriously injured.
A worker says some of the victims were inside the restaurant at the time of the accident.
As of 4:45 p.m., McDonald Avenue was closed from Avenue I to Elmwood Avenue. Avenue I was closed between East 2nd Street and McDonald Avenue.
So far no charges against the driver.
