The man was walking in Beith, North Ayrshire, when the car without a driver struck him and dragged him into a garden, leaving him pinned to the front of a house.
It is understood the vehicle had been parked at the top of a slope without the handbrake on. It mounted the pavement and the man failed to see the car coming towards him round a slight bend.
Rescue crews from Beith and Kilbirnie had to use high pressure airbags to life the vehicle and remove the casualty.
The complex, 30-minute operation saw them first remove concrete steps at the front door of the home to allow them access.
The incident happened at around 12.15pm today in the Townhead area, just off the northbound A737 into Beith, the Scottish Fire and Rescue Service said.
The man was taken to Glasgow's Southern General Hospital with severe head and chest injuries.
Police Scotland are investigating the incident.