Langlais ran as an Action libérale nationale (ALN) candidate in the 1935 election and lost. He was elected as a Union Nationale candidate in the 1936 election against Liberal incumbent Amédée Caron in the provincial district of Îles-de-la-Madeleine. He was re-elected in the 1939, 1944, 1948, 1952, 1956 and 1960 elections.
He was appointed House Whip in 1944 and served as a parliamentary assistant from 1955 to 1960.
He was defeated against Liberal candidate Louis-Philippe Lacroix in the 1962 election. Langlais died on April 6, 1976 in Quebec City.