Myrtle Simpson is originally from Aldershot, but her first job, as a radiographer, was in Fort William where she spent all of her spare time in the mountains as one of the pioneers of Scottish skiing. After learning to ski on the old golf course at Spean Bridge, Myrtle set her sights on higher mountains and travelled to New Zealand where she found many virgin peaks; along with major expeditions to higher peaks such as Mt. Aspiring.

She moved back to Edinburgh and planned an expedition to Peru. With Billy Wallace she sailed out to Lima. Together they climbed six new peaks, each over 19,000 ft and were the first British climbers to reach the summit of the 22,000 ft Huascaran via a new route.

Myrtle Simpson's first expedition to the High Arctic was in 1960, accompanying her now husband, Hugh, to Spitsbergen. They sledged 140 miles to the Planet Range, climbing six mountains and carrying out medical research. With this experience behind them, they accomplished the unsupported crossing of Greenland in 1965. Myrtle then joined Greenland families in their summer hunting camp, where she collected for the Edinburgh Botanic Gardens. Summer canoe expeditions on the west coast of Greenland followed. In 1969, the Daily Telegraph North Pole Expedition, reached 84° 42'N before returning over melting sea ice to Ward Hunt Island in Canada. Numerous journeys to Arctic Canada, Alaska and Greenland followed, including an attempt to traverse Switzerland by ski and canoe in 2007. These many journeys have been documented in her own books and articles, including the National Geographic.

In 1969 Myrtle and Hugh were awarded the Mungo Park Medal by the Royal Scottish Geographic Society for research and exploration in Spitsbergen, Guyana and Greenland. She also received the Scottish Award for Excellence in Mountain Culture in 2013 . Myrtle Simpson was awarded a Polar Medal in 2017 'for outstanding achievement and service to the United Kingdom in the field of polar research' as 'Explorer of Arctic regions; sea canoer, climber and writer'.