After passing his medical examination at Warialda NSW, William, aged twenty nine, enlisted at Narrabri in February 1916 He was a Grazier and the son of Mrs. Mary Thompson of ‘Rocklea’ Yetman.
He joined the 33rd Battalion, 2nd Reinforcement and left Australia on HMAT A15 Port Sydney in September 1916, arriving in England at the end of October. Two months later he was sent to France. William was wounded in action twice, the first time during the battle of Messines in June 1917. The second occasion four months later was more serious and resulted in him being invalided to England where he was admitted to Eastbourne Military Hospital with a gunshot wound to his hand.
William returned to Australia and was discharged in February 1919. After the War he lived in Sydney where he died in 1953. His name is inscribed on the Yetman Honor Roll.