In October 1918, at the age of seventeen, Pier Giorgio enrolled in the Society of Saint Vincent de Paul, in the “Blessed Cottolengo” Conference of the high school of the Social Institute he attended. The Central Council of Turin preserves the minutes in which, in the session of January 8, 1919, his admission to Saint Vincent is attested.
In "Notes for a Discourse on Charity", which serves as a preface to her sister Luciana's book "My Brother Pier Giorgio, La Carità", writes:
“I don’t know if you all know these Conferences of Saint Vincent… A simple institution, suitable for students because it does not imply commitments, only that of being one day a week in a certain place and then visiting two or three families each week. You will see, little time, and yet how much good we can do for those we visit. And how much good we can do for ourselves. The brothers visiting those families are almost, I would say, unworthy instruments of Divine Providence: we approach the poor little by little we come to be their confidants and counselors…””.
On April 15, 1925 he wrote to his friend Isidoro Bonini:
“The other day, while leafing through the calendar, I made a terrible observation: that we are approaching the middle of the month and then I said to myself: Now is the time to intensify my studies and so I decided that as soon as I arrive in Turin I will be dead to everyone except the Conference of San Vincenzo and I will study from morning until evening”.
His last thought before dying was still for the poor followed by his Conference of St. Vincent: he had a box of injections and a policy brought to him, then in trembling, almost illegible handwriting he wrote a note to a brother: “Here are Converso’s injections. The policy is from Sappa: I forgot it, renew it in my name”.