 In August 1873, he married Marion M. Goodwin who had served as a deaconess, nursing the wounded in the Franco-Prussian war.They were wed at St. Paul's, Tottenham, in London, and left for North America soon after their marriage.After his training Collison was appointed by the Church of England's Church Missionary Society (CMS) to Metlakatla, British Columbia, to assist William Duncan (missionary) in converting the Tsimshian people.