Grace Harcourt Clarke was born on 20 January 1863 and married Arthur Walch on 24 September 1884, in Hobart. Arthur was employed at William Crosby and Co., a family merchant and shipping agency, and was a director of J. Walch and Sons Pty Ltd. Grace was an active participant in charitable committees. Their home was in Davey Street, Hobart, and later at Summerhome. They had five children: Grace (who died as an infant in 1890), Margaret Lillian (1892–1971), Christine Martha (1893–1981), Barbara Jane (1895–1987), and James Henry Brett (1898–1991).
Their daughter Christine Walch became a doctor, one of the pioneering generation of women in medicine in Australia. Their daughter Barbara Walch married Gordon Clark, who became a foundation director of Western Mining Corporation, received a knighthood in the Birthday Honours of 1968, and a Companionship of the Order of Australia in 1975.