Sir Chris, who celebrated the milestone birthday earlier this month, successfully scaled the Old Man of Hoy, part of the Orkney archipelago, yesterday – 48 years after his first ascent.
As well as marking his birthday, he hopes his achievement will raise awareness of motor neurone disease.
He lost his wife Wendy to the illness in July and now aims to raise cash for the Motor Neurone Disease Association, Hospice at Home and Cumbria Crossroads, which gave care and support during his wife’s illness.
Before setting off to tackle the 449ft pillar of stone situated off the north coast of Scotland, Sir Chris admitted he was “apprehensive” about the climb.
He said: “I’m apprehensive having reached the age of 80 and having had all too little climbing in recent months because of my wife’s illness.”
Sir Chris was joined by friend and fellow climber Leo Houlding and they were photographed together next to the iconic sea stack. Mr Houlding, 34, said: “Weather’s looking all right. Sir Old Man on Hoy, here we go!”
Sir Chris, who climbed Mount Everest in 1985 when he was 50 after leading and taking part in four previous expeditions to the world’s highest mountain, made the first ascent of the Old Man of Hoy in 1966.
He and colleague Tom Patey returned the following year and were part of a famous three-night live TV broadcast, The Great Climb.
He made the first British ascent of the North Face of the Eiger and the first ascent of the notorious Ogre in Pakistan.
The latter involved fellow climber Doug Scott breaking both legs and Chris suffering fractured ribs. The ascent was not replicated for 24 years.
The outdoor clothing firm Berghaus, of which Sir Chris is non-executive chairman, will post photo galleries and videos of the ascent of the Old Man of Hoy on its Facebook page.
Educated at University College School in Hampstead, he joined the Royal Fusiliers before attending the Royal Military Academy Sandhurst, and on graduation was commissioned in the Royal Tank Regiment in 1956.
After three years in north Germany, he spent two years at the army outward bound school as a mountaineering instructor.
Sir Chris started climbing in 1951, at the age of 16, and over 60 years of adventure has been involved in 19 expeditions to the Himalayas, including four to Mount Everest.
He has written 17 books and presented numerous TV shows about mountaineering.
He has also been active in the outdoor community, with roles in the British Mountaineering Council, Outdoor Industries Association, Council for National Parks, the Outward Bound Trust and, most recently, the Friends of Blencathra.
Yesterday, Matt Hickman of Berghaus, who was with the pair, tweeted: “Chris and Leo are on the top now!”
He had earlier said: “Chris is commenting that he isn’t as flexible as the last time he did it!”
The climbers, who are both members of an elite Berghaus team of athletes, completed their ascent at 5pm yesterday.
News of the adventure led to tributes for Sir Chris being paid on the Berghaus Facebook page.
One user, Rob Mackenzie, posted: “What a legend Sir Chris is, most octogenarians are content to sit and watch life go by. Respect.”
Another, Craig Wilson, wrote: “A true giant and true gent and with Leo’s assistance I’m sure they will conquer this peak.”
Sir Chris was knighted in 1996 for his services to the sport of mountaineering and he was appointed Commander of the Royal Victorian Order (CVO) in the 2010 birthday honours for his services to the Outward Bound Trust.