He and several other Quebec Liberals had broken with their party the year before during the Conscription Crisis of 1944, quitting the party in order to oppose the government's decision to deploy National Resources Mobilization Act conscripts overseas.
Previously, conscripts had only been used for "home defence" and kept within Canada.
He subsequently rejoined the party and, after serving his first term in the House of Commons, ridings were realigned and Dion became a candidate in the new Roberval riding where he won in the 1949 federal election as an official Liberal party candidate.
From 1949 to 1952, he was the House of Commons' Deputy Speaker.
On 8 April 1952, Dion resigned his Parliamentary seat when he was appointed a puisne judge of the Superior Court of Quebec.