New York Police Commissioner Bill Bratton will be leaving his post in September to take a job in the private sector. 

Bratton, who says he will stay on through mid-September 2016 to ease the transition, will be replaced by current Chief of Department James P. O’Neill.

Bratton’s career in the public sector took him from New York to Los Angeles and back again and spanned more than four decades.  Bratton, 68, began as a police officer in the 1970s, became Boston’s and then New York’s police commissioner in the 1990s, and then served as chief of police to the embattled Los Angeles Police Department from 2002 to 2009.

Bratton told City & State in July 2015 that he wouldn’t stay if New York’s mayor, Bill de Blasio, was elected for a second term:

 

He reiterated those comments not long before his resignation, which apparently caught New York City Hall by surprise:

“As long as I’m mayor, I welcome him to continue being police commissioner,” said Mr. de Blasio, with Mr. Bratton to his right and Chief O’Neill at his left, at a previously scheduled news conference on Monday to tout new safety equipment for police officers. “That’s all we have to say about it.”

Bratton’s resignation comes after months of public political arguments with New York’s mayor over staffing and budgets amid complaints about racist practices in the city’s policing policies, and one day after Black Lives Matter activists gathered at City Hall to demand his firing.