He served as a Member of the House of Commons of Canada from 2000 to 2008, and as Minister of Fisheries and Oceans from February 6, 2006 to October 30, 2008.
Hearn was a candidate in the 1989 Progressive Conservative Leadership Convention to replace outgoing Premier Brian Peckford, the eventual winner was Tom Rideout.
As Minister of Fisheries and Oceans, Hearn has been active in defending the controversial east coast seal hunt.
[1] Hearn has also had to deal with the crises in several rural Newfoundland communities involving the sale of fish plants by Fishery Products International to Ocean Choice, often being in conflict with the provincial government, business and unions.
[2] A few days prior to the dissolution of Parliament in September 2008, Hearn announced that he would not stand for re-election in the 2008 election.