After leaving his home in Invercargill at 8.30am on Saturday, Dr Hall-Jones intended a "brisk walk" in Longwood Forest - 45km northwest of Invercargill - in preparation for a planned trip to the Rocky Mountains in the United States.
After completing his walk, or so he thought, he realised he had exited at the wrong place and re-entered the forest.
He soon became lost and realised "I was in a spot of bother".
With darkness falling and the last morsel of food eaten at lunchtime, Dr Hall-Jones remembered the advice of another distinguished Southlander, the late Brigadier James Hargest, to "shiver to keep warm" when experiencing a cold night.
"I took his advice and shivered like anything and soon warmed up."
Dr Hall-Jones also credited his survival blanket, which he has owned for years and had never previously used, with helping him fight off the cold.
"I must get another one. The last one served me well."
After waking up yesterday to the sound of tui at 6.30am, Dr Hall-Jones could "see from his `bedroom' a large farm" in the distance.
He cut himself "to shreds" finding his way out of the bush through gorse until he arrived at the farmhouse at 2pm , where he was welcomed with a "tremendous reception from some typical Southlanders".
After telephoning his wife, who had notified the police he was missing the previous afternoon, he sat down to enjoy two cups of coffee and a pie at the farmhouse, located 5km southeast of where he had parked his car.
Dr Hall-Jones said he was grateful to the couple, and to the police who had launched a search and rescue party at dawn which included members of his Rotary club.
"I was told I am getting a big fine on Tuesday."
A former University of Otago graduate and ear, nose and throat surgeon, Dr Hall-Jones was made an an honorary doctor of law by the university in 2007.
He has written 31 books, many on the history of Otago and Southland.
