Harold McGill was born near Norwood, Ontario in 1878. He graduated medicine in from University of Manitoba in 1905, and until 1907 was house surgeon at Winnipeg General Hospital. He opened an office in Exshaw, Alberta and practised there for one year, leaving to work at the Universities of Chicago and Phildelphia. In 1910 he opened an office in Calgary, and from 1912 also had charge of the health of the Sarcee people. He enlisted in 1914 as medical officer for the 31st Battalion Canadian Expeditionary Force and served in France, transferring to the Canadian Field Ambulance Corps in 1917. He was awarded the Military Cross. In 1930 he was elected as a Conservative Member of Legislative Assembly and in 1932 was made Deputy Superintendent General of Indian Affairs in Ottawa.