John Armitage was born at Failsworth near Manchester on 27 September 1807, the son of Cyrus and Sarah Armitage. During his early childhood, the family moved to Dukinfield in Cheshire. Shortly after he came of age, he accepted an engagement with the Manchester trading house of Philips, Wood & Co. and was sent by them to their branch in Rio de Janeiro. During his seven years in Brazil, he devoted his leisure hours to studying the political institutions and history of the country, and he was said to have 'enjoyed opportunities of intercourse with some of the leading politicians of that country, and has access to state papers'. He wrote A History of Brazil, from the period of the arrival of the Braganza family in 1808, to the abdication of Don Pedro the First in 1831, which was published by Smith, Elder & Co. in two volumes in 1836.
Armitage returned to England, and in 1836 proceeded to Ceylon (now Sri Lanka), where he was a merchant and a member of the Legislative Council. In 1838 he married Fanny Henriette, only daughter of John Jumeaux. He remained in Ceylon for nineteen years, visiting England twice. However, the climate of Ceylon proved injurious to his health, and in August 1855 he sailed for England. Before he left Ceylon, he was presented with an address and a testimonial of silver plate.
On his return to England, Armitage established himself in Manchester, living on Upper Brook Street, where he died on 17 April 1856, aged 48; he was interred at Dukinfield Old Chapel. His will, dated 24 February 1856, was proved on 29 September 1856 (TNA PROB 11/2238/433).
Sources: obituary in the Christian Reformer, vol. 12, no. 137 (May 1856), pp. 317-20; William E. A. Axon, Annals of Manchester: A chronological record from the earliest times to the end of 1885 (Manchester: John Heywood, 1886), p. 269.