William Rawson Elsworth Leach was born at North Sydney on 15 August 1891, the second son of eight children of Samuel and Betsy Leach. He worked as a mechanic in Adelaide and enlisted on 24 October 1916 at 25 years old. Leach stayed at Maribyrnong camp in Victoria for a few months enjoying the city and sneaking out with his friends before embarking on the HMAT Ascanius from Melbourne on 11 May 1917. He arrived in England in July and was placed at the training camp in Salisbury Plains. He then travelled to France where he was a Gunner with the 8th Australian Field Artillery Brigade until the end of the war. William's brother Edwin also enlisted in November 1918, just days before the armistice was signed and was discharged in December of that year.
Towards the end of the war, Leach and a friend toured around Belgium for a week before returning to England. While awaiting his boat back to Australia, he was offered a job in Aberdeen, Scotland at an engineering firm. He took up this position, working with them for a few months. He returned to Australia on board H. T. Anchises on the 22 August 1919.
In November 1919, Leach married Olive Bertha Bradley in Dulwich Hill in Sydney before honeymooning in the mountains. As he and his wife moved around Parkes, New South Wales, Leach returned to work as a travelling machinery salesman. In 1929, Leach was appointed to the New South Wales Commission of the Peace.
Olive and William had a daughter Betsy Frances and a son, Murray Rawson on 4 December 1924, and in the Second World War both Leach and his son enlisted. William joined the army and formed part of the 27 Battalion Volunteer Defence Corps. Murray joined the Royal Australian Navy on 24 August 1942 and served as an Able seaman on the HMAS Cerberus.
William Rawson Elsworth Leach died in Parks on 23 August 1953.