Politician. Born in Kirkintilloch. Johnston was educated at Lenzie Academy and Glasgow University, where he ran the campaign for Keir Hardie (1856 - 1915) to become Rector of the University. He served as Labour Member of Parliament for Stirling (1922-24, 1929-31, 1935-45) and Dundee (1924-29) and as Secretary of State for Scotland in Churchill's wartime coalition cabinet. Johnston was highly regarded as a particularly effective Scottish Secretary, and critically did much to develop the Highlands and attract industry to Scotland. His lasting memorial was the North of Scotland Hydro-Electric Board, which he set up in 1943 to create employment, improve social conditions (only 1% of crofts were connected to an electricity supply) and power new industries. He became the Board's Chairman in 1945, a position which he retained until 1959, by which time most of the Board's generation stations were complete and the supply network had extended to almost 90% of the country. Johnston also acted as Chairman of the Forestry Commission, the Scottish Tourist Board and was a governor for the BBC but, on principle, took no payment for these positions.
He died at his home in Milngavie.