Maurice Cox is leaving his position as Detroit's top planning official in September, the city confirmed Friday.

He is leaving this fall to lead Chicago's planning efforts as its planning commissioner, a city source told Crain's Thursday evening.

Eleanor Gorski is Chicago's acting Planning and Development commissioner, having served in that position since May, according to the city's website.

Cox declined comment Thursday evening other than to say he "looks forward to sharing more information in the coming weeks."

In a Friday afternoon news release, he said the city has "come a long way in building the trust of residents through community engagement and smart planning based on that engagement."

"The infrastructure is in place and the work will go forward to ensure the quality of life for the residents of Detroit continues to improve."

Arthur Jemison, the city's chief of services and infrastructure, said in the release that he "will be taking an active role in the department's operation and will lead the transition" as the city seeks a new permanent planning director.

An acting director will be named before Cox's departure and Katy Trudeau has been promoted to deputy director of planning from her role as executive director of implementation for Mayor Mike Duggan's Services and Infrastructure team. Trudeau replaces Janet Attarian, who left early this year.

The Detroit News first reported Cox's pending departure earlier Thursday evening.

Cox came to Detroit in February 2015 from the Tulane University with an academic background as a heralded urban planner.

Architect Magazine described Cox in October 2016 as "the city's highest-profile planning director since Charles Blessing, who in the 1960s dreamed up a modernist remake of the city that was never implemented."

In his time in the city, Cox came to be known in the development community as having a strong eye for design and a willingness to demand developers and architects to go back to the drawing board if he didn't approve of their concepts.

"I'm bummed," Clifford Brown, managing partner of Detroit-based developer Woodborn Partners LLC, said Friday morning.

"I think Maurice was an advocate for the city and the city's aesthetic long-term in a way that a lot of people don't see. I think he has taken a long view of what the city should look like. He has also been an advocate for equitable development, ensuring that developers who have historically been ignored or pushed to the sideline have an opportunity and a voice."

Aamir Farooqi, a Detroit-based developer who is attempting to redevelop the Stone Soap Building on the east riverfront, lauded Cox's efforts during the design process for the building in 2017.

Farooqi at the time said Cox "held our feet to the fire to come up with a design that the city would be proud of."

"There was every risk that we would end up with something that looked like the duck-billed platypus. It was either that, or a swan, and I think you'll agree we ended up with a swan."

Cox has gone on a bit of a hiring spree, hiring dozens of new planners after starting more than four years ago with just a half-dozen under his oversight. There are now 36, the city said.

Detroit, emerging from municipal bankruptcy with an active central business district and greater downtown, has been a hotbed of real estate activity and its planners and economic development officials have remained active during his tenure.

He has also been a champion for the city's "20-Minute Neighborhoods" initiative geared at creating neighborhoods where residents can get whatever they need from businesses within a 20-minute walk or bike trip.

"Through planning and thoughtful, physical improvements in neighborhoods across the city, Maurice has led the way in improving the walkability and quality of life in our communities," Duggan said in the news release.

Cox held academic positions at the University of Virginia and Syracuse University, and was a City Council member and then mayor of Charlottesville in the mid-1990s and 2000s.

His annual salary is $181,187.50, with $30,000 of that paid by a Detroit Economic Growth Corp. grant.