The Toronto seat recently became vacant when veteran Liberal MPP Laurel Broten stepped down.
Prior to her resignation, Broten had held the seat for 10 years.
Coun. Peter Milczyn was recently acclaimed as the Liberal candidate in that riding and Coun. Doug Holyday has since agreed to be the Progressive Conservative candidate there.
The CBC's Jamie Strashin reported that neither Holyday nor Milczyn will not collect their council pay during the brief byelection campaign.
"I think they need a change at Queen’s Park," Holyday said when explaining his reasons for agreeing to take a run at the seat for the Progressive Conservatives.
Holyday previously made a bid for a provincial seat in 1987, but came in second in that race when running for the Progressive Conservatives in the old riding of Etobicoke-West.
The Tories had previously nominated Steve Ryan, a Toronto police detective, as their candidate in the Etobicoke-Lakeshore riding, but PC Leader Tim Hudak said he is now unable to run in the byelection as a result of an injury.
Hudak tweeted that he was "thrilled" to see Holyday taking the opportunity to run for his party.
Holyday has been one of Mayor Rob Ford's closest allies on council. Both the mayor and his brother, Coun. Doug Ford, have said they support the deputy mayor’s bid for a seat at Queen’s Park.
Five byelections on same day
There will be five byelections held in Ontario on the same day, including two ridings in Toronto and others in Windsor, Ottawa and London. The opposition parties have been critical of the decision to hold them just ahead of a long weekend.
On Thursday, Holyday also expressed displeasure with the timing of the byelections, which he expects will see a much lower turnout than usual.
"I mean, the only other thing they could have done to preclude more people from voting would be to open the polls at midnight," he said.
Ahead of the byelection, both Holyday and his council colleague, Milczyn, said they were ready for the campaign.
"It's certainly not an easy undertaking, I recognize that. Peter Milczyn’s a good candidate and the Liberals have handily won the area the last couple of times, but when you look at the history of the area, it’s been all over the lot — it's been NDP, it’s been Conservative, it’s been Liberal, and we’ll just see," Holyday said, when speaking with reporters. "And right now, federally, it’s Conservative, so there might be changes occurring out there."
Milczyn released a statement Thursday congratulating Holyday on his decision to enter the byelection race, saying he looked forward "to engaging in a thoughtful discussion about our community's future."
The vacancies in the legislature resulted from the departure of five Liberal MPPs in recent months, including former premier Dalton McGuinty.
If the Liberals manage to hang on to all five open seats, they will remain a minority government.
At present, the Liberals hold 48 seats in the legislature, while the Progressive Conservatives have 36 and the New Democrats 18.