[4][5] Delorey entered provincial politics in 2013, defeating Progressive Conservative Darren Thompson and New Democrat cabinet minister Maurice Smith in the Antigonish riding.

[10] In July 2014, Delorey signed an agreement with Pictou Landing First Nation after a blockade of the Boat Harbour effluent treatment facility used by the Northern Pulp mill.

He defeated Progressive Conservative Ray Mattie, New Democrat Moraig MacGillivray, and Atlantica candidate Ryan Smyth.

On June 15, 2017, premier Stephen McNeil shuffled his cabinet, naming Delorey as Minister of Health and Wellness.

[16] On October 7, 2020, Delorey resigned as Minister of Health and Wellness to become a candidate for the leadership of the Nova Scotia Liberal Party.