George Simpson was born in Glasgow, Scotland on 7 November 1863. He was articled to William Spence (1806-1883) of William Spence & Son in Glasgow from 1879 to 1882 during which time he also attended classes at the Andersonian College in Glasgow and the Glasgow Athenaeum. He worked as an assistant to Hugh Barclay (1828-1892) and David Barclay (1846-1917) of H. & D. Barclay in Glasgow from 1882 to 1885, and to John Hamilton (1851-1935) of John Hamilton & Son in Glasgow from 1885 to 1887.
Simpson commenced independent practice as an architect in Glasgow in 1887 He was elected a Licentiate of the Royal Institute of British Architects (LRIBA) in 1911 and a Fellow of the Royal Institute of British Architects (FRIBA) in 1921.
His address was given as 144 Great Hamilton Street, Glasgow in 1881; 98 Great Hamilton Street, Glasgow in 1891; and 6, Milner Road, Jordanhill. Glasgow and 233, St. Vincent Street, Glasgow. in 1911 and 1926. He died at his home, 6, Milner Road, Jordanhill. Glasgow, on 1 November 1926.
Simpson designed commercial premises, libraries, churches, and private houses mainly in the Glasgow area. These included Glasgow Rubber Works (1895); tenement buildings in Elderpark Street, Langlands Road and Uist Street, Glasgow (1899); Bellfield Sawmills in Glasgow (1899); Blackie & Son Printing Works in Glasgow (1899); additions to 6 Victoria Circus, Glasgow (1900); Cooperage, 30, Ruchill Street, Glasgow (1900); Working Men's Hotel, Govan, Glasgow (1905); warehouse for Blackie & Son, 87 Milnbank Street, Glasgow (1906); Bloomvale Carpet Works, 10, Frederick Street, Glasgow (1909); Oil store for P. W. Hall, 22, Kyle Street, Glasgow (1909); Partick Congregational Church, 37, Stewartville Street, Glasgow (1910-14); Possilpark District Library, 127, Allander Street, Glasgow (1911-13); Langside District Library, Battlefield Road, Glasgow (1913-15).
Directory of British Architects 1834-1914. Compiled by Antonia Brodie, et al. Volume 2: L-Z. London; New York: British Architectural Library, Royal Institute of British Architects/Continuum, 2001