His letter to his brother, dated August 1, 1626, inaugurated the series Relations des Jésuites de la Nouvelle-France about the missionary work in the North American colonies of New France.
For the subsequent formation period of his regency, he taught the lower classes at the college in Nevers (1612–15), then studied theology at La Flèche (1615–19).
He then served as a teacher of logic and physics at the college in Bourges (1620–22), and from October 1622 to March 1625 was principal of the boarding school at the Collège de Clermont.
[1] Lalement was made responsible for setting up a mission of the Society of Jesus in New France, and in April 1625 he left Dieppe with Fathers Énemond Massé and Jean de Brébeuf, accompanied by two lay brothers.
Lalemant was quick to realize that the progress of the colony was being impeded by the very people who ought to have promoted it, the de Caëns, who were interested exclusively in the fur trade.
Therefore, as soon as Jesuit Father Philibert Noyrot arrived in 1626 he was ordered, because of the good standing that he enjoyed at the court, to take ship again for France, with the object of advancing the welfare of the colony.
Thwarted by the Trading Company at Quebec in his efforts to evangelize the Indians, Lallemant sailed to France in order to lodge a protest.