Engineer and politician. Although born in Portsmouth (England), Balfour's family had come from Dundee and he began an apprenticeship at the Urquhart Lindsay's Blackness Foundry in that city in 1888. He then joined the firm of Lowden Brothers in the city, of which he later became a Director. He moved to London in 1903 to join the firm of J.G. White & Co. In 1909, he formed a partnership with Andrew Beatty, an accountant with J.G. White, to found the firm of Balfour Beatty.
Under his Chairmanship, Balfour Beatty delivered important contracts including a new tram system in Dunfermline (Fife), a significant role in the Lochaber Hydro-Electric Power Scheme, for the British Aluminium Company (1926), the Grampian Electricity Supply Company's hydro-electric developments and the construction of the Kut Barrage on the Tigris in Iraq (1934-39). He was also well-known for work in Argentina, Uruguay and Malaysia.
Balfour was also Chairman of the Scottish Power Company, the Midland Counties Electricity Supply Company, the Metropolitan Electric Supply Company, the London Power Company and the Lancashire Power Company, as well as being a Director of several other power companies, such that he was highly influential in the provision of electricity across much of Scotland and England, and a pioneer of the National Grid in the 1930s.
Balfour stood unsuccessfully as prospective Member of Parliament for Govan in 1910 and 1911, but went on to serve as Conservative MP for Hampstead (London) from 1918 until his death.