In August 2011, McGrath defeated Peter McCormick and Olympic gold medallist
Mark Nichols to win the Progressive Conservative nomination in the district of
Labrador West. In the
October provincial election McGrath was elected as the MHA, winning 51 percent of the popular vote. On 28 October 2011, McGrath was sworn in as the Minister for Intergovernmental and Aboriginal Affairs and Minister Responsible for Labrador Affairs, and the Voluntary and Non-Profit Sector. On 9 October 2013, McGrath was appointed Minister of Transportation and Works. He resigned as Minister on 29 September 2014, following a report by the Auditor General which indicated McGrath pushed through the cancellation of a multimillion-dollar contract (
Humber Valley Paving Ltd) within hours without notifying senior government officials or the premier. Premier
Paul Davis stated that he would have asked for McGrath's resignation had he not quit first. In the
2015 provincial election McGrath placed third after Liberal victor
Graham Letto and New Democrat Ron Barron.
In 2017, McGrath was elected to the
Labrador City town council. In October 2020, McGrath was chosen as the Progressive Conservative candidate for Labrador West in the province's next election. He was defeated by incumbent NDP MHA Jordan Brown; placing third in the 2021 election. In the 2021 municipal election, McGrath was defeated for re-election. In the 2025 mayoral election, McGrath was defeated by former NDP MHA
Jordan Brown. ==Electoral record==