Toronto's chief planner Jennifer Keesmaat is leaving her role effective Sept. 29 "to pursue other interests," the city announced Monday.

Keesmaat has held the job of chief planner and executive director of the city planning division for the last five years.

In a release announcing her departure, city spokesperson Jackie DeSouza lauded Keesmaat's work on various projects, including the city's first council-approved transit network plan, Ontario Municipal Board reform — as well as some of Toronto's banner transit projects, such as the King Street pilot, the Scarborough subway extension, SmartTrack, and the Eglinton Crosstown LRT.

"I want to personally thank Jennifer for her tremendous passion, leadership and innovation in driving forward a number of major projects for the City as we continue to move Toronto toward becoming a more livable, affordable and functional city," Mayor John Tory said in the release.

Role was Keesmaat's first foray into public service

The role of city planner was Keesmaat's first foray into public service, the city said. Before stepping into that role, she was a principal at a design firm and had worked primarily a planning consultant.

"I promised myself that after five years in public service I would review my future options," Keesmaat said in the release. "I look forward to new challenges in the important business of city building, now enriched by invaluable lessons, new friends and colleagues acquired while serving the people of our great city, Toronto."

The announcement, made mid-afternoon, immediately sparked speculation on social media about the possibility that Keesmaat might be leaving to chase political ambitions.

Are we going to see <a href="https://twitter.com/jen_keesmaat">@jen_keesmaat</a> for mayor? —@iSlutsky

Keesmaat for Mayor. Now there's an interesting thought. <a href="https://twitter.com/hashtag/TOpoli?src=hash">#TOpoli</a> —@MurraySRowe

<a href="https://twitter.com/jen_keesmaat">@jen_keesmaat</a> PLEASE tell me you are running for Mayor! I'm behind you 100% in a campaign against Tory or anyone. <a href="https://twitter.com/hashtag/TOpoli?src=hash">#TOpoli</a> —@ryanlindsay77

No response to speculation about possible mayoral bid

Keesmaat did not respond directly to CBC Toronto's question about a possible mayoral run, instead tweeting the following.

I will be taking a breather and spending some time with my family. I will continue to champion the city that I love, Toronto. <a href="https://twitter.com/hashtag/ThankYou?src=hash">#ThankYou</a> —@jen_keesmaat

A political run by Keesmaat wouldn't be a surprise to urban planner Sean Galbraith, who says the volume of projects she oversaw during her time in the role was "unprecedented."

"I think that Jen did amazing work to raise the public profile of planning in Toronto and the planning department. She was a very different style of chief planner, one that was needed in the department," Galbratih said.

"I think it's also fair to say that her style wasn't always appreciated by all of council, and there was a not-infrequent conflict there. You only need to look to the Gardiner East debate for that."

Keesmaat famously clashed with the mayor on the so-called "hybrid" plan to leave much of the aging elevated expressway in place, when she advocated to have it torn down.

That prompted questions to the mayor about whether his office moved to clamp down on Keesmaat talking publicly about the matter.

"At the end of the day she has been free to express her opinion," Tory told CBC's Metro Morning host Matt Galloway in June 2015.

"The only thing, generally, I think public servants should not be doing is sort of debating politicians because they are public servants and there is a line to be drawn there."

Best civil servants 'speak truth to power'

Coun. Joe Mihevc is one person at city hall who appreciated Keesmaat's outspoken style.

"I regard the best senior civil servants as those who speak truth to power, who don't try to suck up to the political powers that be," he said commenting on her resignation.

Coun. Joe Mihevc says this isn't the last the city will hear from Keesmaat but that her ambitions don't include a mayoral run. (CBC)

"That's the kind of thing that lasts longer than the job itself. You can leave this job saying, 'I did my work ... I had the integrity to speak the truth as I saw it.'"

As for whether Keesmaat might be considering political office, Mihevc says this isn't the last the city will hear from her but that her amibitions don't include a mayoral run.

"And she doesn't need to have them. She's a very good planner and sometimes you can do much better work in a planning position than on the political side."