Earlier commissioners were mostly deputy ministers in various ministries (Minister of the Interior, Mines, Mines and Resources).
As commissioners are appointed by the Government of Canada, they are not a vice-regal representative in the territory — that is, unlike in Canada's provinces, there is no such thing as a "territorial Crown" analogous to the provincial Crowns. The commissioner represents the federal government and must follow any instructions of the Cabinet or the relevant federal minister, currently the Minister of Crown-Indigenous Relations and Northern Affairs.
Since 1980, the territories have had self-government, with the legislature choosing a government leader or premier, in addition to electing members of parliament to the Parliament of Canada.