George Frederic Allen was born in London in 1837, the son of Maria and George Allen, who was a noted architect.
After training as an architect and surveyor, George somehow secured a job as an engineer for the Great Barrier Kauri Timber and Copper Mining Company in New Zealand, arriving in July 1860.
The company went broke, so he got a job teaching at the Church of England Grammar School in Auckland.
Allen then started up an architecture and surveying practice with James Barnard.
William Fox, a future premier of New Zealand, appointed them as district surveyors for the Wellington Province. Allen was moved to the Whanganui area in 1862. Not long after, when the New Zealand Wars intensified in this region, surveying became too dangerous to practise in isolated areas. Allen became a teacher again, opening a private school. He was also an active militiaman and was present at the relief of Pipiriki, where a force of 200 Taranaki Military Settlers and Patea Rangers had built redoubts and were subsequently trapped by Maori from the upper river.