In the nineteenth century, it was not considered unusual for a senator to be Prime Minister.
Today, it is rare for senators to occupy prominent positions in cabinet.
There have been a few rare occasions when the leader of the government in the Senate was not included in the cabinet by virtue of a separate ministerial appointment, such as William Benjamin Ross who served in the position in 1926, and Walter Morley Aseltine and Alfred Johnson Brooks who were not included in the cabinets of Prime Minister John Diefenbaker from 1958-1963.
In 1968, the position of leader of the government in the Senate became an official Cabinet position in its own right with the appointment of Paul Martin, Sr. (father of Canada's future prime minister, Paul Martin).
[3] Retired civil servant Peter Harder was named to the position on March 18, 2016.