Dupuis was born in Riviere du Loup, Lower Canada around 1817. He entered the service of the Hudson's Bay Company in 1839 and served as a middleman at Fort Durham (1842) before being transferred to Fort Victoria in 1843 where he served continuously until his retirement in 1852. In 1847 he was promoted from middleman (annual salary £17) to dairyman (annual salary £20). Dupuis was married to an unnamed woman in a group ceremony involving five other HBC servants on July 19, 1848 at Fort Victoria. Throughout his tenure he worked with the fort livestock; most often with cattle, but also with pigs, horses and oxen. He also worked under the guidance of Angus McPhail and together they operated two dairies providing the fort with milk and butter. In May of 1849, Dupuis' dairy, which was somewhat isolated from the fort, was the site of a murder of a young 'Indian lad' employed there. The incident touched off a state of alarm and a brief armed conflict between some members of the Songes and the Cowichans ensued. Dupuis and others were hesitant to return to the site and the dairy was eventually closed in July. Both Dupuis and McPhail retired to live and farm in Saanich in the mid 1850s. Dupuis married as many as four times and fathered five sons. Some records suggest that he assumed the name 'Joseph' later in life and, following his death on December 31, 1874, was the first to be buried in the Catholic Cemetery of the Church of the Assumption, Saanich.