[2][3] Mercier was educated at St. Paul's College and the University of Manitoba Law School, and practiced as a lawyer before entering political life.
The latter two positions were merged as one ministry on October 20, 1978, and were separated again on November 15, 1979, when Mercier was named Urban Affairs minister and Government House Leader.
Lyon's government was defeated in the 1981 election, although Mercier successfully sought re-election in the safe Tory seat of St. Norbert rather than in the marginal Osborne riding.
[2] Mercier held a unique position in caucus for the next few years, being one of the few individuals who was on friendly terms with supporters of party leader Gary Filmon and potential challengers Clayton Manness and Don Orchard.
Mercier lost a narrow contest against Liberal candidate John Angus in the 1988 election,[2] in which the Progressive Conservatives formed a minority government under Gary Filmon.