Balfour was born in Edinburgh on 21 March 1873 to Thomas Alexander Goldie Balfour. Balfour was educated at George Watson's College before matriculating to Edinburgh University. He graduated from Edinburgh with a MB, CM degree in 1894 and joined his father's medical practice. Within two years of leaving Edinburgh University, Balfour returned to education when he entered Caius College at Cambridge University as an advanced student. Balfour spent his time in Cambridge specialising in the prevention of disease, the field in which he would concentrate the rest of his medical career. He studied under Kanthack, performing research work on typhoid fever, and later spent a period of study at Strasbourg, before taking the D.PH. at Cambridge in 1897. He completed his MD in Edinburgh in 1898; his thesis on the toxicity of dyestuffs in relation to river pollution winning him the student gold medal. He returned to the University of Edinburgh to earn a BSc in Public Health in 1900
In April 1900, Balfour travelled to South Africa to serve as a civil surgeon in the Second Boer War. He was posted to Estcourt as part of No. 7 General Hospital and later given duty at the pestilential typhoid camp in Pretoria. Later in the campaign he was put in charge of the British Garrison and Boer Laagers at Kaapsehoop. While in South Africa, Balfour contracted typhoid and returned to England before the end of 1901. During his time in South Africa, he came under the influence of the prominent Scottish parasitologist Patrick Manson, and from this period he became an ardent student of tropical medicine.
Balfour married in September 1902 to Grace, daughter of G Nutter of Sidcup, and the same year he was made the director of the Wellcome Tropical Research Laboratory in Khartoum in Sudan where he also took up the post of Medical Officer of Health. Within two years he was appointed sanitary advisor to the Sudanese government. His new role within Sudan allowed Balfour to move in high-profile social circles, bringing him into contact with the likes of Lord Cromer, Lord Kitchener and Sir Reginald Wingate. During his time in Khartoum, he reduced deaths by malaria by 90 per cent through the removal of mosquito breeding grounds and improving the city's clean water systems and sanitation. In 1907 the Khedive awarded him the Fourth Class of the Imperial Ottoman Order of Osmanieh. The same period also saw Balfour contribute to four reports produced by the Wellcome Laboratory and in 1911 he co-wrote with Major R.G. Archibald a review of the advances in tropical medicine, which anticipated the work of the Tropical Disease Bureau which was set up in 1912.
His time in Africa also saw Balfour oversee the introduction of a floating laboratory, a gift from Dr Henry Wellcome to the Sudan Government. This allowed the department to conduct scientific work in the upper reaches of the Nile, and aided the understanding of diseases of the blood. Balfour's most notable work during this period was on spirochaetosis. He was appointed Companion of the Order of St Michael and St George in the 1912 King's Birthday Honours. After suffering from ill-health in Africa, he returned to Britain in 1913, to found the Wellcome Bureau of Scientific Research in London, and to organise what would later become the Wellcome Museum of Medical Science. 1913 also saw Balfour travel South America and the West Indies for research purposes.
With the outbreak of World War I, Balfour again joined the British war effort. Serving in the Royal Army Medical Corps, he reached the rank of Lieutenant-Colonel. Originally posted in France in 1914, he was later a member of the medical advisory committee in Mudros, Salonica and Egypt. After returning to England he was given the role of scientific adviser to the Inspector Surgeon General of the British forces in East Africa. During the war he was appointed Companion of the Order of the Bath in the 1918 New Year Honours, and was Mentioned in Despatches on 12 February 1918. He relinquished his commission on 31 May 1919. In 1920 he was awarded the Mary Kingsley award by the Liverpool School of Tropical Medicine.
In 1923 Balfour was appointed Director of the London School of Hygiene & Tropical Medicine, and oversaw the construction of a new school. He also served as president of the Royal Society of Tropical Medicine and Hygiene in 1925–1927. His papers are available from the archives at the London School of Hygiene & Tropical Medicine.
In 1929 he suffered from a nervous breakdown, believed to have been caused by the pressures of his new post; and although the British Medical Journal reported he fully recovered; other sources state his breakdown was complete. In the 1930 New Year Honours he was promoted KCMG, thus becoming Sir Andrew Balfour; but was later admitted to Cassel Hospital in Penshurst, Kent to be treated for clinical depression.
His uncle was John Hutton Balfour botanist and 7th Regius Keeper of the Royal Botanic Garden Edinburgh and Her Majesty's Botanist.
Balfour was a keen sportsman, and as a youth was an amateur boxer and notable rugby player. His first came to note as a rugby player when he represented Watsonians, a club for former pupils of George Watson's College. It was while representing Watsonians that he was selected to play for the Scotland national team, in the opening game of the 1896 Home Nations Championship against Wales. At the age of 22, he was placed into his favoured position in the pack, in a Scottish team that contained two fellow Watsonians, Harry Oswald Smith and Robin Welsh. Wales won the game by two tries to nil. Despite the loss, Balfour would play in the remaining two games of the tournament, a scoreless draw away against Ireland and then an impressive win over England, which gave Scotland the Calcutta Cup for the fourth successive year. The following season (1896/97), Balfour had enrolled at Cambridge and won a place in the Cambridge University team. He played in the first of two Varsity Matches at the end of 1896 winning his first sporting 'Blue' in a victory over Oxford University.
Just a month later, the 1897 Home Nations Championship was underway, but Balfour was not selected for the national team, and would not rejoin the team until the final match of the competition, an away encounter with England. Scotland lost the game and Balfour never represented the team again. Balfour was still in favour with Cambridge, and was part of the University team to win the Varsity Match in 1897.
After his playing career came to an end, Balfour continued his association with rugby union as a supporter of London Scottish F.C., and became a national selector for the Scottish Rugby Union. During the 1929/30 season, Balfour was made Vice-President of the Scottish Rugby Union, the President being Sir Augustus Asher. The next season Balfour took on the role of President of the SRU, but did not complete the term due to his untimely death.
Outside the medical profession, for which he wrote several papers and publications, Balfour was also a keen writer of adventure novels. In 1897, while still at Cambridge University, he completed and saw published, his first novel By Stroke of Sword. Balfour's novels were mainly historical adventures, often set in Scotland and many having connections with his own medical background. His final novel, The Golden Kingdom (1903) stands out as a lost race novel, described by The Encyclopedia of Science Fiction as being "under the influence of H. Rider Haggard and Robert Louis Stevenson".
MedicalMedicine, Public Health and Preventive Medicine (with C. J. Lewis, 1902)
Memoranda on Medical Diseases in Tropical and Sub-Tropical Areas (1916)
War Against Tropical Disease (1920)
Reports to the Health Committee of the League of Nations on Tuberculosis and Sleeping Sickness in Equatorial Africa (1923)
Health Problems of the Empire (with H. H. Scott, 1924)
NovelsBy Stroke of Sword (1897)
To Arms! (1898) Available at OpenLibrary
Vengeance is Mine (1899) Available at OpenLibrary
Cashiered and Other War Stories (1902)
The Golden Kingdom (1903) Available at OpenLibrary
Balfour died in 1930 during his residence at Cassel Hospital. His frozen body was found on 30 January in the grounds of the hospital after he had fallen from a window. He was survived by his wife and two sons.
He is buried in Edinburgh with his parents in Grange Cemetery. The grave lies in the south-west section close to the central embankment containing the vaults. The headstone has fallen and is currently (2015) lying on its back.