Originally known as the New Brunswick House Band of Ojibway, the Ojibway people who during the fur trade era traded primarily at the New Brunswick House posts at Brunswick Lake and Missinaibi Lake became a signatory to Treaty 9. Originally, the Band had reserved for themselves the 17,280 acres (6,993.0 ha) New Brunswick House 76 Indian Reserve, but on June 1, 1925, the Ontario government established the Chapleau Game Preserve which surrounded (and did not explicitly exclude) the New Brunswick House reserve and was closed to all hunting and trapping. The Ontario government subsequently purchased reserve land from the federal government in 1928. In 1947, the federal government purchased a tract of land in Mountbatten Township from the Ontario government and established the Mountbatten 76A Indian Reserve. The Band moved to its present reserve at Duck Lake 76B Indian Reserve after 642 acres (259.8 ha) of the Mountbatten 76A were exchanged in 1973 for an equivalent area of land closer to Chapleau, Ontario.
Brunswick House First Nation elects their leaders through the Act Electoral System, consisting of a Chief and three Councillors. The current Chief is Kevin Tangie. Together with Councillors Charmaine Saunders, Majorie Tangie and Irene Redbreast, their current term ends on August 10, 2015.