Steen, along with his brother Robert, was a city councillor in Winnipeg. Robert Steen later became the city's mayor from 1977 until he died of cancer in 1979.

Steen, who worked as a life underwriter with Equitable Life of Canada, was first elected as an alderman in the old city of Winnipeg in 1969, and reelected as a councillor in Queenston ward after the city amalgamated into Unicity in 1971.

Steen went on to be elected as a Tory MLA in Crescentwood, defeating Liberal leader Charles Huband in 1975. He was reelected in 1977 and again won when he ran in the new riding of River Heights.