Firmin was born in Canada in 1854. He married Caroline Dube at St. Eloi in 1873 and they had at least two sons and two daughters. Firmin emigrated to Lowell, MA and lived at Gaudette's Block on Tucker Street. His occupation was a laborer. He died of pneumonia at the young age of 37. He had at least two sons: Magloire and Ernest, who lived in Lowell, and two daughters who lived in Canada: Mrs. Joseph Levesque of St. Paul de la Croix and Mrs. Joseph L'Heaureux of Canada.