Blanchet was born into a devout Catholic family in Quebec in 1795 where he was ordained in the Sulpician seminary in 1819. In 1838 he was given jurisdiction over all of the Oregon Territory as vicar-general to Archbishop Signay of Quebec. He arrived at Fort Vancouver accompanied by Father Modeste Demers in 1838 for the purpose of evangelizing among the numerous native tribes as well as attending to the spiritual welfare of the Hudson's Bay Company servants and other settlers. Blanchet is credited with creating "The Catholic Ladder" (also called "The Sahale Stick"); a visual tool widely used to facilitate communication of the Catholic doctrine to indigenous people. He was appointed Archbishop of Oregon City in 1846 and was active in church affairs until 1879 when he wrote Historical Sketches of the Catholic Church in Oregon. He died in Portland, Oregon in 1883.