Chicago Mayor Rahm Emanuel announced on Tuesday that he will not seek re-election for a third term in office, NPR reports.

Emanuel, a former White House chief of staff, has remained a controversial figure in Chicago, where gun violence increased in recent years and relations between police and the communities soured.

“I’m not shy and, together, we’ve never shied from a challenge. Today, the time has come to make another tough choice,” Emanuel said at a news conference. “As much as I love this job and will always love this city and its residents, I’ve decided not to seek re-election. This has been the job of a lifetime, but it is not a job for a lifetime.”

Emanuel was elected mayor of Chicago in 2011, becoming the city’s first Jewish mayor. He was re-elected in 2015.

Before taking on the job as mayor of the Windy City, Emanuel served as U.S. congressman for Illinois’ 5th District and was former President Barack Obama’s chief of staff for two years.

In a statement to U.S. News and World Report, Obama praised Emanuel for his work in Chicago. 

“Chicago is better and stronger for his leadership, and I was a better President for his wise counsel at a particularly perilous time for our country,” Obama said. “Whatever he chooses to do next, I know he’ll continue to make a positive difference, just as he has throughout his career in public service.”

According to Chicago’s public radio station WBEZ, Emanuel’s decision not to run for a third term is seen as shocking, since his re-election campaign raised more than $10 million.