Charpentier began covering Parliament for Ottawa's Le Droit (the cities largest newspaper) in 1922. His stories on the then-unilingual English environment of Parliament were believed to be instrumental in getting federal authorities to increase the visibility of French in Canada. Over the course of his career, Charpentier also wrote for Montreal La Presse and Quebec Le Soleil. His resume included serving as a media spokesman for ambassador Georges Vanier in Paris and working in some francophone African nations and South America. He was also Canada's chief press censor during the Second World War. He was appointed editor-in-chief of Le Droit following his diplomatic career in 1968 at the age of 71.
Charpentier was still writing weekly columns on his trusty typewriter for Le Droit until 1999, when he had to stop due to chronic bronchial pneumonia at the age of 101.