Scott was born in Nottingham, England and started climbing at the age of 12, his interest sparked by a school trip to the White Hall outdoor activities centre near Buxton.

Scott's mountaineering career includes over 30 expeditions to inner Asia and he is regarded as one of the world's leading high altitude and big wall climbers. He is best known for his first ascent of the south-west face of Everest with Dougal Haston in an expedition led by Chris Bonington. All of his other climbs have been in the lightweight alpine style.

Highlights of Scott's climbing career include

• 1975: South-west face of Everest with Dougal Haston, bivouac on the south summit at 8760 m.
• 1977: Baintha Brakk, more commonly known as The Ogre (in Pakistan), and descent with both legs broken at the ankle.
• 1978: Attempt of the west side of K2.
• 1979: North ridge of Kangchenjunga (8586 m).
• 1979: Ascent of the north side of Nuptse with Georges Bettembourg, Brian Hall and Alan Rouse.

Scott has climbed the Seven Summits, the highest peak on each of all seven continents. He is a past President of the Alpine Club and was made a CBE in 1994. In 1999 he was awarded the Patron’s Medal of the Royal Geographical Society. He was presented with the Golden Eagle Award by the Outdoor Writers and Photographers Guild in 2005.

During Scott's climbing career, his understanding of the culture and the people in the regions where he climbed grew as he formed strong bonds and relationships. Scott founded the charity Community Action Nepal and spends much of his time fundraising for this cause, especially from giving public lectures. Scott is also an advocate of Responsible Tourism. Scott set up his own trekking agency in 1989, and pays the porters and other staff double the going rate, with improved working conditions, porters' loads being reduced and clothing purchased to combat the cold and rain.