Lyall was born in England, but moved to Canada as a child. She later studied art for a short period in Hamilton, Ontario under the prominent portraitist J.W.L. Forster, before travelling to London to attend the South Kensington School of Art and then to Paris, where she became a student of the Académie Colarossi.
Her most famous painting, Interesting Story, was completed during her stay in Paris. It was later purchased by the Government of Ontario and exhibited in the Legislature for many years.