 MacAdam was a member of the Legislative Assembly of Prince Edward Island from 1996 to 2006, representing the electoral district of Morell-Fortune Bay as a member of the Progressive Conservative Party.At the age of 29, he was named Minister of Fisheries, becoming the youngest cabinet minister in the history of Prince Edward Island.MacAdam also stood as the federal Progressive Conservative candidate in Cardigan in the 2000 federal election, losing to Lawrence MacAulay by a margin of less than 300 votes.