Born at Listowel, Ontario, Walker learned water colour technique in Toronto and studied briefly in New York but was largely self taught. In 1883 he settled on the Ile d'Orléans where for more than fifty years he painted scenes of rural life. Elected to the Royal Academy of Canada in 1918 he became its President in 1925. His portrayals, in the traditional manner, of figures and animals won international acclaim and his work is displayed in major American galleries as well as in the National Gallery of Canada. He died at Ste. Pétronille.