Johnson was a cabinet minister in the government of Hugh John Macdonald, and was named speaker of the assembly in 1904.

[1] Johnson was first elected to the Manitoba legislature in a by-election held on November 27, 1897 in the constituency of Turtle Mountain following the death of John Hettle.

Johnson was re-elected as an official Conservative candidate in the 1903 provincial election, and was chosen as speaker of the assembly on January 7, 1904.

The Conservative administration of Rodmond Roblin was forced to resign from office in 1915, amid a serious corruption scandal.

Johnson lost to George McDonald[3] by thirty-six votes, in a rematch from the previous year.