George Farquhar Pennington was born in Castleford, Yorkshire, England on 22 April 1872 and was articled to William Henry Thorp (1872-1944) in Leeds, Yorkshire from 1888 to 1891. He then worked as an assistant to F. G. Corke in Eastbourne, Sussex and to George Moxon in Barnsley, Yorkshire. He commenced independent practice in Castleford in 1894 and from c.1894 was in partnership with Samson (Sam) Howard Garside (1861-1948) as Garside & Pennington in Pontefract, Yorkshire. Garside's son, Darrell Godfrey Garside (1893-1933), later became a partner in the practice.
The London Gazette 1 April 1927 announced that the partnership had been dissolved on 30 March 1927 as Darrell Godfrey Garside had retired from the firm, however, it is not known if the remaining partners continued the practice.
Pennington was a Member of the Society of Architects (MSA) and was elected a Licentiate of the Royal Institute of British Architects (LRIBA) in 1911. He lived in Castleford and Pontefract, Yorkshire until the 1930s. By 1939 he had moved to St Ives, Cornwall. He died on 30 May 1961. At the time of his death his address was given as 19 The Avenue, Chichester, Sussex