Police said they were called to Ford’s Road, off Gorgie Road, just before 4am on Thursday and found the man dead.
The street was taped off for several hours with a forensics tent set up at the scene.
Divulging details of the incident to the Daily Record, a police source said the man was stabbed to death after confronting joyriders who had crashed into his car while he was asleep.
“The victim was said to be sleeping in his car when the joyriders hit it,” the source said.
“He got out and confronted them and they stabbed him before making off. The victim is not known to police at all. It’s tragic.”
In an official statement, Police Scotland say enquiries into the man’s death are ongoing.
Detective Inspector Stuart Alexander of Police Scotland’s Major Investigation Unit said: “This death is very much unexplained and we are still in the early stages of our investigation.
“We are eager to establish the full circumstances leading to the discovery of the man’s body and are investigating a number of lines of inquiry, including the potential that a Peugeot vehicle has been involved in this incident.
“I would ask anyone who either lives or was driving in the areas of Fords Road, Stenhouse Avenue and Stevenson Drive, along with surrounding streets, in the early hours of Thursday, March 7, and saw any vehicles driving erratically or at speed or any other suspicious behaviour, to get in touch with us at their earliest convenience.
“I would also ask anyone who has any private CCTV or dashcam footage in these areas that can assist with our investigation to come forward immediately and allow our officers to view it.”