The work of the Bollandists had just been revived and, in spite of his youth, Victor de Buck was summoned to act as assistant to the hagiographers. He remained at this work in Brussels from September 1840, to September 1845. After devoting four years to theological studies at Louvain where he was ordained priest in 1848, and making his third year of probation in the Society of Jesus, he was permanently assigned to the Bollandist work in 1850. He remained engaged in it until his death, living in a room at St. Michael's College, Brussels, which also served as his study. He had already published in Vol. VII of the October "Acta Sanctorum", which appeared in 1845, sixteen commentaries or notices that are easily distinguishable because they are without a signature, unlike those written by the Bollandists. In the early years, he would periodically take a brief respite to preach a country mission in Flemish.