MINNEAPOLIS — Minneapolis Police Chief Medaria Arradondo said Monday he will retire next month, another blow to a department still in crisis after the murder of George Floyd by one of his officers.

Arradondo, a veteran beat officer who rose up the ranks and was appointed the city’s first Black chief in 2017, had been credited with trying to transform a department long accused of racism and brutality, especially against residents of color.

He quickly fired the four Minneapolis officers implicated in Floyd’s May 2020 slaying, and later made headlines when he testified against Derek Chauvin, the first of the officers tried and convicted of Floyd’s murder.

But Arradondo, 54, acknowledged at a news conference Monday that Floyd’s killing and the unrest that followed, including the burning of a police station, had ultimately taken a personal toll. Though Mayor Jacob Frey and other community leaders had pressed the chief to stay on for another three-year term as the city tries to reshape its approach to policing, Arradondo said he would leave the department in mid-January.

“After 32 years of service, I believe that now is the right time to allow for new leadership and perspective, new focus and new hope to lead the department forward in collaboration with our communities,” Arradondo said.

Frey, who joined Arradondo at the news conference, said he expected to appoint an interim chief as early as this week and would conduct a national search for Arradondo’s replacement.

But Frey acknowledged the challenges of finding new leadership for a department that has struggled in the harsh glare of the international spotlight after Floyd’s murder and is facing both state and federal investigations into its policing practices.

“We want to make sure that we get the best, most talented person that is reform-minded, that is procedural justice-oriented and wants to ensure the safety of every resident throughout our city,” Frey said. “This is a responsibility that I will take very seriously.”

More than 300 officers have left the department since Floyd’s killing — roughly a third of the authorized force. The departures have coincided with a dramatic uptick in violent crime across the city, leaving the department struggling to respond to 911 calls.

At the same time, complaints have continued about the behavior of Minneapolis officers — most recently last week, when a White officer was captured in a viral video taking down and arresting a 64-year-old Black man at a grocery store as bystanders yelled that the man had done nothing wrong. Charges against the man were later dismissed.

Last month, Minneapolis voters soundly rejected a ballot initiative that would have replaced the police department with a new public safety agency — a campaign in which Arradondo became a central figure. Frey and others who opposed the amendment regularly invoked Arradondo, warning residents that a vote in favor of replacing the department would eliminate the “reform-minded” police chief’s job.

Just days before Election Day, Arradondo spoke out against the ballot initiative, warning that it could further damage a police department that was already “flatlining” and threaten the city’s safety. Still, Arradondo at the time pointedly declined to say whether he would stay in the job for another term.

On Monday, Arradondo insisted he had made his decision to retire in recent days, after “thoughtful discussions” with his family and with Frey and considering his “own personal well-being.”

Arradondo, a South Minneapolis native, began his career in 1989 as a beat officer on the city’s predominantly Black north side, joining the department at a time when there were few Black officers in the ranks. He worked his way up — serving stints in the homicide bureau and in internal affairs. In 2007, he and four other Black officers sued the city for racial discrimination, alleging they were passed over for promotions and treated unfairly because of their race. The city settled that lawsuit in 2009 for $740,000.

In 2017, Mayor Betsy Hodges tapped Arradondo to replace Janee Harteau as police chief, as the city grappled with the fatal police shooting of Justine Ruszczyk Damond. Later reappointed by Frey, Arradondo promised to heal the growing rift between the community and its police force — a pledge that was disrupted by Floyd’s murder.

Though Arradondo and Frey later passed numerous police reforms — including a ban on chokeholds and knee restraints like the one used on Floyd — the outgoing chief acknowledged Monday that his lasting legacy is likely be defined by Floyd’s murder and the tumult that followed, though he expressed a desire to be remembered differently.

“I think that if there are two words or two things that people use to describe me and hopefully describe my legacy, it’s that I cared and I tried,” Arradondo said.