Pierre Raoux was the son of the unmarried Francisca Lagast. After her wedding with the carpenter Edmond Raoux, Pierre was legitimized as his son in 1850. He seems to have been brought up outside the family by the Broeders van Liefde during at least a part of his childhood. As a lower class boy he went to the Brugean Academy of fine arts where he was able to develop his artistic talents and became a laureate more than once in the 1860’s. Employed by the printer Jean Petyt he learned the lithography technique and when Jean Petyt died in december 1860, he remained an employee in the printing office continued by the widow Petyt. The printing office Petyt brought him into contact with key figures of the Brugean cultural and catholic society, such as Adolf Duclos and Jean Baptiste de Bethune, who supported his further development. A scholarship of the Belgian state allowed him to go abroad in 1874. During an internship in Paris he specialized himself in chromolithography. With the financial support of Jean Baptiste de Bethune and Henri Desclée, probably thanks to Adolf Duclos who kept contact with him, he subsequently travelled to Italy for a long time to study and copy the works of the old masters there. They requested him to collect iconographic material and margin decorations from medieval manuscripts and early printed books for their liturgical publications. De Bethune wanted to make him head of the lithographic department of the Sint-Augustinus society, the Brugean branch of the Desclée publishing house. As Raoux refused this proposal his most valuable studies were copied for Desclée and the Saint Luke school in Ghent, as a compensation for the investments.
In October 1879 Raoux started his own lithography house in Bruges together with his wife Leonie Manceau. He produced large quantities of high quality, neo-gothic printings, but had to struggle against the mass production of so called “saint-sulpice” prints that flooded the market and were considered lascivious and irreligious. In this struggle he was supported by Guido Gezelle and the Heilige Beeldekensgilde. He also contributed to magazines including Rond den Heerd and the Proceedings of the History Society. In October 1886 he was appointed teacher at the Brugean Academy of fine arts. Eventually, in 1889, he did become head of the lithographic department of the Sint-Augustinus society (Desclée De Brouwer).