Plamondon was first elected to the Canadian House of Commons in the 1984 federal election, defeating Liberal Party incumbent Jean-Louis Leduc in Richelieu. The Progressive Conservatives won a landslide majority government in this election under Brian Mulroney's leadership, and Plamondon entered parliament as a government backbencher. He was associated with the Quebec nationalist wing of his party and soon became known as a . In 1986, he criticized justice minister John Crosbie for appointing an anglophone to replace the sole francophone judge on the Ontario Court of Appeal. He later criticized industry minister Sinclair Stevens for awarding a multimillion-dollar untendered contract to a shipbuilding company in Quebec City. Plamondon also expressed sympathy with fellow MP Robert Toupin, who left the Progressive Conservatives in May 1986 to sit as an independent.