After making his studies under the Fathers of the Society of Jesus, Lallemant entered that order in 1605, having completed the usual course of study and teaching for new members. He was ordained and taught philosophy and theology for some time until he was made master of novices, an office he filled for four years. Having exercised it with success he was appointed director of the fathers in third probation; after three years in this difficult post he broke down in health, and was sent to the college of Bourges, in the hope that change of occupation would restore him. The hope was not to be fulfilled; he died after a few months.
Lallemant has been called the Father Alvarez of France; his ideals and efforts to meet them were as uncompromising as the latter's. Like Alvarez, Lallemant expected of others what he did himself. He set the high ideal before his disciples, especially the Fathers of the third probation (Third Year), and required them to rise to such ideals. He is known today chiefly by his “Doctrine Spirituelle”, a collection of his maxims and instructions gathered together by Father Jean Rigoleuc, one of his disciples, and detailing very thoroughly his spiritual method.