He served in the Legislative Assembly of Alberta from 1935 to 1955 as a member of the Social Credit caucus in government.

Masson ran for a seat to the Alberta Legislature as a Social Credit candidate in the electoral district of Wainwright for the 1935 general election.

He defeated three other candidates in an open race with a large percentage of the vote to pick up the seat for his party.

He faced three other candidates, among them Albert Blue, a former Social Credit MLA whose district, Ribstone had been abolished after redistribution and who now ran under the banner of the Independent Progressive Association.

His popular vote dropped slightly compared to 1944, but he won the three-way race to keep his seat.