Toronto Mayor David Miller says TTC chair Adam Giambrone is leading the transit system into a "renaissance" and should not step down in the wake of a sex scandal.

Miller said Giambrone deserves to be judged for his work with the transit system, rather than his personal life.

"I haven't asked him for his resignation, and I don't intend to," Miller told reporters Thursday, saying he has "confidence" in Giambrone.

"This is the most remarkable period for the TTC in the last 30 years. There's a renaissance in public transit in Toronto," said Miller, stressing that this was a result of Giambrone's work.

Miller said that under Giambrone's leadership, the TTC ordered upgraded streetcars, buses, and subway cars and increased service on bus routes.

He also praised Giambrone as the reason for increased ridership and expanded customer service initiatives like the online trip planner launched a few weeks ago.

"There hasn't been a time like this before, and it's because of him, and he deserves credit for that," Miller said.

"I'm going to stand by him as chair of the TTC and he deserves an opportunity to finish the job."

Giambrone dropped his bid for mayor Wednesday. At a short news conference he apologized to his live-in girlfriend Sarah McQuarrie for being unfaithful with multiple women.

The councillor for Ward 18 (Davenport) took the action in the wake of reports by a 20-year-old woman who told the Toronto Star she had a relationship with him.

Kristen Lucas says the relationship included sex on his city hall couch. She also says Giambrone gave her confidential information about TTC business, such as a looming fare hike. Miller was asked if the integrity commissioner should conduct an investigation.

The city's code of conduct for members of council calls on them to conduct their private lives in a way that withstands close public scrutiny. In addition, they are not to disclose any confidential information acquired through their office.

"I actually believe I have addressed this issue," Miller said. "As I've said, I'm not going to get into his personal life. I think what's happened has been extremely sad and Mr. Giambrone has been accountable for everybody for it -- everybody."

Some of Giambrone's opponents aren't as forgiving.

Coun. Peter Milczyn (Ward 5, Etobicoke-Lakeshore) thought Giambrone should step down as TTC chair.

"Tomorrow we're going to have an urgent meeting to discuss how we're going to deal with the blue-ribbon panel on customer service and from what I understand, the chair is on some kind of romantic -- or not-so-romantic -- getaway to Paris right now," he said.

Coun. Michael Walker (Ward 22, St. Paul's) said he hopes that when Giambrone arrives back from vacation, he will decide to step down as TTC chair.

Miller said Giambrone's private life should not jeopardize his post.

"I believe that even when you're elected you're allowed to have a private life and make mistakes," Miller said.

The TTC's eight commissioners would be the ones who could fire Giambrone, if it came to that. Only four of eight could be reached by CTV Toronto on Thursday, and none called for Giambrone to resign.

The TTC faced a publicity nightmare in recent weeks when angry riders took photos showing at least two fare collectors sleeping on the job. Another rider took a video of a bus driver's seven-minute unscheduled break.

Miller acknowledged the TTC is facing "issues," but said Giambrone deserves a chance to resolve them.

"He's developed a strategy to address that and it's a very important thing he needs to do to complete that strategy and that's why I haven't asked him for his resignation and I don't intend to," Miller said.

On Thursday, Giambrone's Facebook fan page said he is running for re-election in his Davenport ward.

However, on Friday, a spokesperson for Giambrone's office said that page is unofficial. The councillor has not yet made a decision on whether or not he will run to retain his Ward 18 seat, the person said.

Meanwhile, rival Ana Bailao, who lost to Giambrone in 2003, announced she was ramping up her campaign ahead of the Oct. 25 election.

With a report from CTV Toronto's Alicia Markson