John Lorne MacLeod, born on 20 October 1873 at Inveraray, was the eldest son of John MacLeod, a Prison Governor, and Mary MacLeod (nee McTavish), of County Buildings, Tobermory
His siblings were Williamina, Phoebe, Duncan, and James.
His sister, Phoebe, married George Whigham, a solicitor (SSC), and John lived with the Whighams at 23 Albany Street, Edinburgh, while he was studying law at the University of Edinburgh. From 1905 he was in partnership with his brother-in-law as Whigham and MacLeod SSC at 25 Albany Street. When, in 1909, George died, John moved his law practice to Great King Street, still trading under the name of Whigham and MacLeod. He lived with his sister, who died in 1925, at Woodbine, Colinton, Edinburgh.
He served as a member of Edinburgh City Council from 1905 to 1919, representing Canongate Ward, and was City Treasurer from 1912 to 1914. From 1916 to 1919, he served as Lord Provost and Lord-Lieutenant of Edinburgh.
From 1925 until his death he was chairman of the Scottish Life Assurance Company. He served as Food Commissioner for Scotland from 1920 to 1921 and was a member of the Royal Commission on Food Prices in 1924–1925. He was also chairman of the Consumers' Committees for both Scotland and Great Britain and from 1924 to 1929 served as chairman of the Jute Trade Board for Great Britain. He was chairman of the General Nursing Council for Scotland from 1921 until his death. He also was active with a range of organisations promoting Highland and Celtic culture, including being a member of the Clan MacLeod.
Having already been knighted, he was appointed Knight Grand Cross of the Order of the British Empire (GBE) in the 1920 Birthday Honours for his services as Lord Provost of Edinburgh during the First World War.