In 1525, having completed a preliminary course of studies in his own country, Francis Xavier went to Paris, where he entered the College of Barbara. Here he met Ignatius of Loyola, who was already planning the foundation of the Society of Jesus, and Pedro Fabro. They were instrumental in changing the attitude of Francis by dinning into his ears the famous words of Jesus: What does it profit a man to gain the whole world if he loses his soul?

He became one of the first members of the Society of Jesus and took his vows with Ignatius and five others on 15th August 1534, in a small chapel in Montmartre, to serve Jesus in poverty and chastity. After leaving Paris, Francis went, with the rest of the members of the newly papal-approved Jesuit order, to Venice to be ordained to priesthood, which took place on 24th June 1537. The first objective of Ignatius and his companions had been to make a pilgrimage to Jerusalem. While waiting in Venice, Italy, to depart for the Holy Land, Xavier worked in a hospital, aiding those in need. When fighting between Venice and the Ottoman Empire made a trip to Jerusalem impossible, Xavier instead went to Rome, where he and others in the society offered their services to the Pope. They presented themselves to the Pope to go anywhere and to always be at his disposal.