Born in Edinburgh in 1873, Balfour spent his initial career as a medical doctor, but moved into preventative medicine as something he put into practice when he joined the Boer War as a Civil Surgeon. On his return he met Sir Patrick Manson who encouraged him to take the Diploma in Tropical Medicine & Hygiene at the London School of Tropical Medicine. Between 1904 and 1923, Balfour worked with the Wellcome Tropical Research Laboratory and then the Wellcome Bureau of Scientific Research, where his achievements included being appointed Inspector General to East African Command. In 1923, Balfour was made the first Director of London School of Hygiene & Tropical Medicine. It was Balfour who recommended and proposed that the present School should be established and built; prior to this it was considered that a school attached to a hospital.