Hamish Macinnes founded the Glencoe Mountain Rescue Team and the Search and Rescue Dog Association, invented his own ice axe and stretcher and wrote the first International Mountain Rescue Guide.
But the life of Mr MacInnes, who went on four expeditions to Mount Everest, was turned upside down after he was diagnosed with dementia after suffering a series of infections and dramatic weight loss.
He was sectioned and detained in a psychiatric hospital in the Highlands after being found disorientated outside his home in Glencoe by a neighbour.
The film recalls how Mr MacInnes, who worked with Clint Eastwood and Robert De Niro on blockbuster movies like The Eiger Sanction and the Mission, tried to escape from hospital at one point in a bid to regain his freedom.
Final Ascent, which the 88-year-old will help launch at the Glasgow Film Festival next month, examines how he “clawed” his way back to a full recovery by poring over his vast archive of photographs, films and books on his exploits on the mountains in the Highlands and around the world.
The actor Michael Palin, who made several films with Mr MacInnes after the pair met during filming of Monty Python and the Holy Grail in Glencoe, appears in Final Ascent and is expected to join the mountaineer at its premiere on 3 March.
Director Robbie Fraser had no knowledge of Mr MacInnes’s illness when he started to make the documentary until the mountaineer spoke on camera for the first time.
Mr Fraser said: “He went on in that interview to describe being sectioned, a bewildering and deeply traumatising experience for a man who had spent so much of his life in pursuit of the sense of freedom given by climbing.
“He described over the course of that interview – and his hospital notes bore out – how he managed to make his way to the roof of the hospital, pursued by staff who presumably thought he was suicidal. But, in fact, he was simply trying to return to his happy place – the highest point available.
“When he came out of care, all memory of his previous life had gone. What he did next seems extraordinary. As well as undergoing physical and psychological rehabilitation with the help of his friends, he seems to have rebooted his mind.”
Speaking in the film, Mr MacInnes said: “I find it very difficult to remember, because I was so ill. It’s all very hazy, like looking through a very dense filter. I was found unconscious at the back door. I think I was pretty close to dying.
“Somehow or other I had contracted this urinary disease. It was a terrible thing. I went down from 14 to eight-and-a-half stone.
“I was taken in a vehicle. I knew from certain landmarks they were taking me in a circle. After that I found it quite distressing as I was sectioned and sent into confinement. It’s the only way I can put it.
“I had this obsession or desire to get out because I’d been used to the open air all my life. To be cloistered there was quite a restricting mental and physical experience. I lost my memory completely, not just for a few hours, but for two or three months.
“Memory is obviously very complex. One of the ways I clawed my way back to sanity was to watch all my own films. It’s quite an interesting thing. You feel as if you are a spectator looking in. This was how I refreshed. Every morning when I woke up a bit of the puzzle would come out.”
In the film, Palin recalls the shock of visiting Mr MacInnes in hospital after embarking on several expeditions with him.
He said: “There was just something about Hamish’s presence. He had this aura about him that made you feel you were going to be okay and that he would get you down if anyone could.
“I heard that he was ill and then I heard that he had been taken to a mental hospital against his will. No-one could find out why he was taken there.
“I found this much reduced figure sleeping in one small room. I noticed the bed was very narrow. It looked as though he was on some expedition.
“I wanted to say to them: ‘This man has been up most of the Himalayan mountains.’ It seemed such as extraordinary place for Hamish to be.”