Birth records are unclear as to whether Collison was born in County Armagh, Ireland.
In August 1873, he married Marion M. Goodwin who had served as a deaconess, nursing the wounded in the Franco-Prussian war.
Collison was ordained at Metlakatla in 1879, by Bishop William Bompas who had travelled overland from Red River for this purpose.
[1] In the early 1890s he and his family moved to Kincolith, a Nisga'a village on the Nass River in northern B.C., founded as an Anglican mission by the medical missionary Robert Tomlinson.
Collison is best remembered for his vivid 1915 memoir In the Wake of the War Canoe, which contains numerous ethnological insights, including information on the nearly extinct Tsetsaut people, remnants of whom lived at Kincolith.