Mary Buchanan was born in Paisley, near Glasgow, Scotland in 1876 and studied at Paisley School of Art and Glasgow School of Art. She moved to Paris in 1911. She lived at 18 Boulevard Edgar-Quinet, Paris and worked in the studios of Antoine Bourdelle (1861-1929) and Ossip Zadkine (1888-1967). She returned to Paisley in 1914 where she lived until 1926 when she moved to Chipstead in Surrey and lived there until at least 1936.

She mainly produced portrait figures and busts, in a range of mediums including bronze, marble, wood and limestone.  exhibited at the French Salon in Paris in 1911 and at the Salon des Artistes Français in Paris in 1912. She also exhibited at the International Society of Sculptors, Painters and Gravers, Society of Women Artists and Royal Academy in London; the Royal Glasgow Institute of the Fine Arts; and the Royal Scottish Academy in Edinburgh. She appears not to have exhibited after the late 1930s.  She died in London in 1958.