[1] Her mother, Jane McNeil McMurdo, moved from Scotland to North America with her husband and infant daughter in 1836.

In 1871 her long-standing guide, Melchior Anderegg, learned that a contemporary Meta Brevoort, an American female mountaineer, was planning an expedition to climb the Matterhorn.

Walker's party hastily rearranged their plans and on 21 July, she became the first woman to stand atop the Matterhorn, and with it gained world renown.

As well as the Eiger she had already been the first woman to climb the Aiguille Verte (1870), Lyskam (1868), Gross Fiescherhorn (1868), Schreckhorn (1867), Weisshorn (1866), Dom (1866), Rimpfischhorn (1864), Grand Combin (1864), Zumsteinspitze (1863), Finsteraarhorn (1862) and the Strahlhorn (1860).

In 1909 she became a member of the newly formed Ladies' Alpine Club where she was acclaimed as the pioneer of women climbers.