John was born in Manorhamilton in August 1817. His father George took the family to Canada in 1824 when John was just seven years old. George became a contractor who worked on the construction of several canals. In later life be entered politics and was a founding member of the Canadian senate. The Crawford family settled in Brockville, east of Toronto, during the 1840s. A lawyer by profession, John acted as solicitor for the Grand Trunk Railway. In 1867 he was appointed Queen’s Counsel. He served for a time as president of the Royal Canadian Bank. He also became president of the Toronto and Nipissing Railway and a director of the Toronto Grey and Bruce Railway. Crawford was a member of the Legislative Assembly of the Province of Canada for East Toronto from 1861 to 1863. He later served as a Member of the Canadian Parliament from 1867 to 1873 and supported representation by population. He was appointed Lieutenant Governor of Ontario on 12th November 1873. His tenure of the office was relatively short, however. Following several months of poor health, he died at his official residence, Government House, on 13th May 1875. In 1845 he had married Toronto woman, Helen Sherwood, and they had a family of one son (who later represented Brockville in the House of Commons) and five daughters.