Colin, a son of James and Ellen Irwin, enlisted at Inverell in September 1915. He was a twenty-four-year-old bush labourer and gave his address as Ashford NSW. He was one of thirteen volunteers farewelled by a large crowd at Inverell Railway station at the end of September.
Colin became a member of the Anzac Cyclist Battalion, 2nd Reinforcements and sailed from Australia for Egypt on HMAT A46 Clan MacGillivray in May 1916. By August he had arrived in England and was sent to France in September where he was transferred to the 53rd Battalion. At the end of the year he was sent back to England and admitted to Birmingham Hospital for treatment for trench feet. He returned to his unit in France in June 1917. Three months later he was wounded in action, invalided back to England and admitted to Norfolk War Hospital, Norwich. He had a gunshot wound to his leg which resulted in amputation below the knee. Colin was returned to Australia and medically discharged in May 1919.
After the war he married and lived in Sydney where he worked at the artificial limb factory. He died in Sydney in 1962. His war diary is held by the Australian War Memorial.
Colin has his name recorded on the Ashford, Graman and Inverell Honor Rolls.