He made the first winter ascent of Crowberry Ridge Direct and of Raven's Gully on Buachaille Etive Mòr with Chris Bonington in 1953. He designed the first all-metal ice axe, and is credited with introducing the short ice axe and hammer with inclined picks for Scottish winter work in the early 1960s. He pioneered the exploration of the Glencoe cliffs for winter work with the Glencoe School of Winter Climbing and for many years led the area's Mountain Rescue team. He is recognised as having developed modern mountain rescue in Scotland, setting up the Search and Rescue Dog Association and the Avalanche Information Service, and inventing the MacInnes stretcher, which is used for rescues worldwide. In 1975, MacInnes was deputy leader to Bonington's Mount Everest Southwest Face expedition, which included Dougal Haston and Doug Scott.