Gabriel-Elzéar Taschereau was born at Quebec City, the son of Thomas-Jacques Taschereau. At the age of 14, he aided in the defence of the town against the British attack in 1759. He later became a member of the Legislative Assembly and Legislative Council of Lower Canada, as well as a seigneur and a judge. Taschereau inherited the seigneury of Sainte-Marie-de-la-Nouvelle-Beauce from his father and acquired the seigneuries of Jolliet and Saint-Joseph-de-Beauce and a part of Linière, Mingan and Anticosti Island.