McNicoll was born in Toronto to an affluent family. Her parents were David McNicoll and Emily Pashley. McNicoll became deaf in early childhood due to scarlet fever, and as a result, focused her energies on playing the piano and developing a keenly observant eye.

As a young woman, she attended the Art Association of Montreal, beginning her studies under William Brymner in 1899. In 1902, she moved to England to study in London at the Slade School under Philip Wilson Steer.

Painting in The Open Air

At the Slade, students were encouraged to paint en plein air. Later, McNicoll studied in St Ives, Cornwall with Algernon Talmage, where she met Dorothea Sharp, a fellow artist who became a lifelong friend. McNicoll and Sharp traveled together to France and Italy  sharing studio space, and posing for each other’s paintings.

A member of the Royal Society of British Artists and an associate of the Royal Canadian Academy of Arts, McNicoll died in Swanage, Dorset, at the early age of thirty six. An obituary described her as “one of the most profoundly original and technically accomplished of Canadian artists.” Source: Wikipedia.