After studies at Saint-Eustache school, he went at 16 to Saint-Benoît, Mirabel[2] to learn the commercial business, as an apprentice of the merchant Duncan McGillis.

Masson devoted all his energy to develop his business, and admitted wanting to "beat" and "break down" his competitors.

[2] To transport his products, he bought a new boat of 290 tons, he gave it the name of his wife, "Sophie".

[2] Also related to transport, he asked the Legislative Assembly to build a canal; he created a shipping company and initiated the construction of a railway.

[2] Masson also invested in urban utilities of water supply and Gas lighting, in Montreal, in Quebec and in Toronto.

At the invitation of his associates, he made an initial investment in Montreal, and his participation in 1842 reached more than a third of the société du Gaz de Montréal.

[2] Masson was one of the few businessmen in this time to make substantial profits using credit to develop his business.

He managed to double his business volume systematically using credit; but he had trouble to convince his Scottish partner to do the same.

[7] He was militia captain from 1823, member of the Board of Trade of Montreal, first churchwarden of Notre-Dame parish and judge of the peace.

[8] But he was a patriot when he hid Louis-Joseph Papineau, who had a bounty on his head in 1837, and in 1845 when he agreed to be elected the third president of the Association Saint-Jean-Baptiste.