Newall Hunter, from Leadhills, South Lanarkshire, battled thick snow and bad weather, as temperatures plunged to -40C for his final climb to the summit of Denali in Alaska on 24 June.
The storms were so violent that Mr Hunter was trapped in his tent for five days at 14,000 feet and a further four days at 17,000 feet where he had to dig his tent out of the snow every two hours to prevent it from collapsing.
The 52-year-old had attempted to climb the peak – nicknamed the world’s coldest mountain – in 2010 but terrible weather forced him to retreat after spending six days trapped at 17,000 feet as the mercury fell to -47C in his tent.
The 6,200 metre peak completes the so-called Grand Slam, which demands climbers ascend both Everest and Kilimajaro, as well as Europe’s highest peak Mount Elbrus, in the Caucusus, the Carstensz Pyramid in Indonesia, and Aconcagua in South America.
After reaching the South Pole he went on to climb Mt Vinson, the highest peak in Antarctica.
Mr Hunter has become the first Scot and the 14th person in the world to acheive this feat, which was the culmination of more than 13 years of climbing and skiing to the most remote corners of the world.
Mr Hunter, who works as an IT security consultant, said: “Denali is probably the most difficult of all seven peaks so I thought I would leave it until last.
“The rest of them were quite straightforward. When you climb Everest you have sherpas but here you really on your own.
“The weather is particularly tough, as it is definitely the coldest of all. It’s all snow.”
As part of the feat, Mr Hunter, who now lives in Gloucestershire, became the first Briton to ski solo from the Ronne Ice Shelf to the South Pole during an arduous 570-mile trip last year.
He reached the famed spot on 4 January, having spent his birthday on Christmas Eve, Christmas Day and seeing in the New Year pulling two heavy sleds with his equipment across the polar ice cap when at times visibility was so bad he could not see beyond the end of his skis.
At one point he narrowly avoided disaster when the snow collapsed beneath his skis to reveal a gaping crevasse.