Nassau County police say the car slammed into the Dunkin' Donuts in Valley Stream around 3:30 p.m. Thursday.
The man who was pinned was taken to a hospital where he was listed in serious condition with internal injuries.
Two other customers, ages 55 and 60, the driver and his 85-year-old passenger suffered minor injuries.
Four employees in the restaurant weren't hurt.
The car was impounded for brake and safety checks.
According to Newsday, police say alcohol was not a factor in the accident.