Matthews was a Progressive Conservative member of the Newfoundland and Labrador House of Assembly from 1982 to 1996.

He is a former Parliamentary Secretary to the Queen's Privy Council for Canada and Minister of Intergovernmental Affairs, Deputy House Leader of the Progressive Conservative Party, and Progressive Conservative critic of Fisheries and Oceans.

In March 2007, Matthews called Prime Minister Stephen Harper a "liar."

[3] In October 2018, Matthews was appointed as Chief of Staff to provincial PC leader Ches Crosbie in the Opposition Office.

[4] Matthews contested the 2019 provincial election as the PC candidate in Burin-Grand Bank,[5] but was defeated by Liberal incumbent Carol Anne Haley.