He was born in Paris on May 25, 1606, and was the son of a secretary to King Henri III of France. He joined the Jesuit seminary in Clermont in 1624 and was ordained in 1635. His father initially forbade him from travelling to Canada where he would face almost certain death as a missionary, but he was eventually allowed to go and arrived in the colony of New France in 1636. He spent the rest of his life as a missionary among the Hurons, never returning to Quebec. The Hurons nicknamed him "Ouracha," or "rain-giver," after his arrival was followed by a drought-ending rainfall. He was greatly influenced by fellow missionary Jean de Brébeuf, and was known as the "lamb" to Brebeuf's "lion." When Brébeuf was killed in March of 1649, Garnier knew he too would soon be killed. On December 7, 1649 he was indeed killed by the Iroquois during an attack on the Huron village where he was living. He was canonized in 1930 by Pope Pius XI with the other Canadian Martyrs, and his feast day is October 19.