A newly installed Toronto councillor has resigned after her old social media posts, which appear to show homophobic content, were unearthed hours following her appointment.

Rosemarie Bryan was appointed by city council as the new councillor for Ward 1 – Etobicoke North during a special meeting on Friday, filling the vacancy left by Michael Ford, who ran in June's provincial election and won.

After she was appointed, however, Bryan's alleged past social media activities, which appears to show her sharing anti-LGBTQ content, were brought to light.

Friday was the start of the Pride Toronto's Festival Weekend, which features the return of the Pride Parade to downtown streets on Sunday following a two-year hiatus.

Several councillors posted to social media that had they known about Bryan's posts, they would not have voted for her to fill the seat.

"A majority of councillors would have never this (way) had this information been brought forward. We relied too heavily on the recommendation being made by former councillor," Coun. Mike Layton tweeted.

"We need to reopen this debate."

Of the 23 councillors who cast their ballots, 21 voted for Bryan, including Mayor John Tory.

Coun. Josh Matlow, one of the two councillors who did not vote for Bryan, called for her resignation, tweeting that he does not believe "anyone who supports hate and bigotry should be a Toronto city councillor, or hold any public office for that matter. This is disgraceful."

On Friday night, Bryan released a statement announcing that she is resigning, saying it's the best way to continue serving those who love and support her in Etobicoke North.

Bryan said she is devastated that her past online posts are being "thrown against my decades of commitment to the community."

"I recognize councillors were not aware of those posts before today's discussion and now that they are, I recognize many would not have cast their vote for me. I don't want to hurt all those who supported me and I remain committed to helping my community in any and every way I can," she said.

In a statement, Tory said while Bryan made a "strong case" to council for her appointment, her past social media posts are "not acceptable."

"I totally disagree with any homophobic or transphobic views. I absolutely support our 2SLGBTQ+ residents. City Councillors are expected to set an example when it comes to consistency with our shared values," Tory said.

"I would not have voted for this appointment had I been aware of these posts and I know that is the sentiment of the vast majority of council who also voted today."

He said it was appropriate for Bryan to resign.

"The upset this has caused everyone involved is extremely unfortunate. This is especially unfortunate on the very weekend when we are celebrating the progress we have made together," Tory said, adding that he has asked staff to review the overall appointment process.