Tech Moves covers notable hires, promotions and personnel changes in the Pacific NW tech community. Submissions: tips@geekwire.com

Michael Mattmiller has resigned from his post as chief technology officer for the City of Seattle.

Mayor Jenny Durkan announced Mattmiller’s resignation in a press release Friday. Mattmiller became CTO in 2014. In 2015, the Seattle Information Technology (SIT) department was formed under former Mayor Ed Murray to centralize the disparate IT groups across city government.

Before taking the CTO role, Mattmiller was a senior strategist in Microsoft’s cloud business. Prior to that position, he spent more than a decade in the Washington D.C.-area doing risk assurance and data management consulting work for PricewaterhouseCoopers.

“I did make the decision to depart the City,” Mattmiller told GeekWire in an email. “It was a difficult decision, but after four years serving our public it is a good time to return to the private sector.”

Mattmiller didn’t provide additional details about why he’s leaving or where he is headed next. Last summer, Mattmiller played a leading role in a Crosscut article titled, “At City Hall, a massive department is mired in chaos” detailing employee complaints and inefficiencies at SIT.

Tracye Cantrell will take over as interim CTO as Durkan’s office searches for a replacement. Cantrell is SIT’s chief of staff.

“Michael has led one of our largest departments and aimed to make Seattle one of the most innovative cities on the frontline of emerging technology,” Durkan said in a statement.