Delorey entered provincial politics in 2013, defeating Progressive Conservative Darren Thompson and New Democrat cabinet minister
Maurice Smith in the Antigonish riding. On October 22, 2013, Delorey was appointed to the
Executive Council of Nova Scotia as Minister of Environment and Minister of Gaelic Affairs. Since being appointed Minister of Environment, he has passed the Importation of Hydraulic Fracturing Wastewater Prohibition Act, and has taken steps to deal with the seven million gallons of wastewater in
Debert, Nova Scotia. In March 2014, he provided conditional approval for the
Goldboro, Nova Scotia Liquefied Natural Gas project, which will turn Goldboro into the “energy hub” of Nova Scotia by 2018. The project will lead to a marine terminal and a natural gas liquefaction plant in that community. 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. The agreement allowed Northern Pulp to continue its work to repair a broken pipe that had spilled effluent near a First Nations burial ground, and will lead to a timeline for the closure of the Boat Harbour Effluent Treatment Facility. On July 24, 2015, premier Stephen McNeil shuffled his cabinet, naming Delorey as Minister of Finance. Delorey was re-elected in the Antigonish riding following the 40th Provincial General Election on May 30, 2017. He defeated Progressive Conservative Ray Mattie, New Democrat Moraig MacGillivray, and Atlantica candidate Ryan Smyth. Liberals and Progressive Conservatives saw their vote shares increase from the previous election while the NDP saw a decline. On June 15, 2017, premier Stephen McNeil shuffled his cabinet, naming Delorey as Minister of Health and Wellness. 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. == Leadership campaign ==