James Boag III was born in Launceston on 14 Aug 1881 to James Boag II (1854-1919) and his wife Elizabeth Edwards. He was educated at the Launceston High School in Milton Hall. His teacher in 1893 was Martin Cheek. On 17 Feb 1909 James married Florence Emma Matear. They had three sons: James IV, born on 8 Dec 1909 at Tulloch Street, Launceston; George, born on 13 Jan 1913 at New Town (Hobart) and Peter, born on 19 May 1915 at Trevallyn.
James took over as Managing Director of the Boag's Brewery operations in Feb 1919 after his father died and was Northern Director of Tasmanian Breweries Pty Ltd. He was an alderman on the Launceston City Council from 1937 until 1940. He was a rower, horseman, amateur boxer and played bowls and golf. He was a member of the Northern Club, Launceston Club, Commercial Travellers' Association and Rotary. He died aged 62 on 4 Aug 1944 at the Homoepathic Hospital in Launceston. His funeral was held at Chalmers Church, Frederick Street, followed by cremation at Carr Villa. At the time of his death his son James (Bill) was in the RAAF and Peter was in the Merchant Navy. See The Examiner 14 Jan 2006, p. 27.