He was especially known for his popular fiction recounting adventures and quirks of life in the Chilcotin-Cariboo, and for a regular column that appeared for many years in the Vancouver Sun.
One of his novellas set in the Chilcotin, Breaking Smith's Quarter Horse, was adapted into a feature film starring Glenn Ford.
Also starring in that film was Chief Dan George, who played the character Ol' Antoine in the CBC-TV series Cariboo Country, based on his stories.
Because it was easier St. Pierre was one of the "flying MPs" whose ridings spanned whole European countries in size, and where many voters were distant from the capital and living in areas difficult to get around in, never mind to.
His books are classics of the cowboy genre and also constitute documents of individuals and notes on local natural history and myth, and serve as portraits of the cultures of the Chilcotin, Cariboo and Nechako districts of British Columbia.