He was a mountain safety advisor to a number of major films, including Monty Python and the Holy Grail, The Eiger Sanction and The Mission.

[2] His father's surname was McInnes, but Hamish, (according to his obituary in The Times) "later adopted the more distinctive Scottish spelling of the family name".

[7] He went on to complete the first winter ascent of Crowberry Ridge Direct and of Raven's Gully on Buachaille Etive Mòr in the Scottish Highlands, with Chris Bonington in 1953.

[8]: 188 [9]: 148  He was also a part of the group that scaled the Bonatti Pillar on the Aiguille du Dru, a mountain on the Mont Blanc massif of the French Alps.

[11] He is credited with introducing the short ice axe and hammer with inclined picks for Scottish winter work in the early 1960s.

[11][19][20] In 1972 he was part of an 11-strong team that attempted to be the first to ascend the southwest face of Everest, but their expedition did not reach the summit due to bad weather.

[21] In 1975, MacInnes was deputy leader to Bonington's Mount Everest Southwest Face expedition, which included Dougal Haston and Doug Scott.

[11] He was involved with a number of films, as climber, climbing double and safety officer, including The Eiger Sanction and The Mission.

[34][35] In 1994 MacInnes resigned his position as leader of the Glencoe Mountain Rescue team, over a decision taken by his colleagues to let the BBC make a documentary based on their work.

[18] In 2018 a documentary film was produced for BBC Scotland, titled Final Ascent:The Legend of Hamish MacInnes.

Introduced by his friend, Michael Palin, it recounts the story of MacInnes's life and achievements, and how he used archive footage, his photographs and his many books to "recover his memories and rescue himself".

[45] Until 1998, he resided at "Allt Na Reigh", a cottage within the glen that was subsequently purchased by media personality, Jimmy Savile.