The man, named locally as the prominent lawyer Thomas Friel, was discovered in a house at Silverwells Crescent in Bothwell, South Lanarkshire, shortly after 2pm yesterday.
A spokesman for Police Scotland said enquiries were at an early stage and that the man was being treated in hospital, although the extent of his injuries was not known.
Shocked neighbours said the street had been filled with police officers for most of the afternoon and that the road had been taped off for a short period.
Forensic science officers were also seen entering the house.
One friend who lives nearby said: "I was on my way to visit Mr Friel, just to drop in on him, when we were stopped from entering Silverwells Crescent by the police.
"There were around five police cars in the street and an ambulance. I could see officers in white overalls coming and going too.
"I don't know what's happened but I hope he's alright."
Bothwell, adjacent to Uddingston in South Lanarkshire, is a popular retirement spot for upmarket couples and was formerly the home of the Celtic player Henrik Larsson and Scotland manager Gordon Strachan.
The friend added: "Seeing so many police officers in the street was very shocking and not something you expect in the tranquil setting of Bothwell."