Born at Bath, Somerset on 10 January 1824, he was the eldest of five sons of Samuel Peace Pratt by his wife Susanna Martha Hodgson (d. 1875). After education at Haileybury College (1844–6), he matriculated at London University in 1844. In 1847 he joined the East India Company's service at Calcutta. He became under-secretary to the government of Bengal, and inspector of public instruction there. While in India Pratt in 1851 helped to found the Vernacular Literature Society which published Bengali translations of English literature, and acted as secretary till 1856. He also started a school of industrial art. In 1857 Pratt was at home on leave and at contributed to The Economist on Indian matters. He finally left India in 1861.
