Penzone became the top law enforcement officer in America’s fourth largest county in January 2017 after defeating then-Sheriff Joe Arpaio.
The sheriff’s office has been under scrutiny for years for various controversies, including a ballooning list of unresolved misconduct cases.
“I will continue to work in the realm of serving this community in different capacities,” Penzone said. He said he has plans to do something “significant” but did not elaborate.
During the press conference, Penzone highlighted his accomplishments a sheriff, which he said included reducing the agency’s spending and debt, assisting the county in keeping elections secure and closing Tent City, the notorious open-air jail that Arpaio created.
“It represented all the things that are wrong about incarceration and law enforcement," Penzone said of Tent City, which he closed in 2017. “It was degrading and it tried to pass this message as though by disrespecting and mistreating inmates that suddenly it would change behavior. And that was nonsense.”
The Maricopa County Board of Supervisors will select Penzone’s replacement, who will serve until the current term ends in January 2025. Voters will elect a successor to a full four-year term in November 2024. State law dictates that the Republican-led board replace Penzone with another Democrat.
Fields Moseley, communications director for the county, said the board will determine the process for picking a new sheriff. With past vacancies of elected officials, he said, the board has accepted letters of interest, resumes and recommendations and asked applicants to fill out a questionnaire before interviewing candidates.

Will Joe Arpaio run again for sheriff?
Arpaio, now 91, helmed the sheriff's office for 24 years, and his scandal-ridden tenure made the office synonymous with racial profiling, abuses of power and police misconduct. In 2022, Arpaio lost his race for mayor of Fountain Hills — a wealthy, conservative town in the eastern reaches of Maricopa County where he lives. Arpaio lost by little more than 200 votes. He said in July that he's going to run again for mayor.
On Monday, when told of Penzone's announcement, Arpaio said he's not interested in running for sheriff.
"So right now, I'm running for mayor, and I don’t feel I may run for sheriff right now," Arpaio told Phoenix New Times. "I felt deep down that I had a suspicion that he was going to do some other things.”
Arpaio said he didn't always agree with Penzone's policies as sheriff but credited him for having "loyalty and character."
"I always said he’s the current sheriff and he does what he feels is right. I have no problem with that," Arpaio said.
"As far as running for sheriff, I did my 24 years and served Maricopa County, and we’ll see what happens in the sheriff's race," he added.

Elected officials react to Penzone’s announcement
Penzone’s announcement on Monday prompted a bipartisan avalanche of reactions from elected officials, including U.S. Rep. Greg Stanton, Arizona Attorney General Kris Mayes, Secretary of State Adrian Fontes, Maricopa County Attorney Rachel Mitchell and Mayor Kate Gallego.Stanton said Penzone served the county with “distinction and integrity.”
Paul Penzone has served Maricopa County with distinction and integrity his entire career—spending 21 years as a @PhoenixPolice officer before being elected Sheriff.
— Rep. Greg Stanton (@RepGregStanton) October 2, 2023
At @mcsoaz, his commitment to public safety and service to our community has been second to none. pic.twitter.com/FyRadd3PRr
Mayes said the sheriff brought “humility, integrity and respect back to the leadership” of the sheriff’s office.
Sheriff Penzone brought humility, integrity & respect back to the leadership of @mcsoaz. It's been a joy & honor to work alongside him. Through his servant leadership, he made headway on the fentanyl crisis, child safety & human trafficking prevention. Sheriff, we are grateful. https://t.co/7PmSvFb6mI
— AZ Attorney General Kris Mayes (@AZAGMayes) October 2, 2023
Fontes praised Penzone for “his commitment to the safety of election workers and voters in a time of unprecedented threats and harassment.”
“Even on the hardest days when there were very serious threats being hurled at me and my staff, I always felt safe knowing Paul and his team were always watching out for us,” Fontes said in a prepared statement. “When a wave of threats of violence, harassment and intimidation occurred during the 2020 elections, there was no book on how to keep vulnerable election workers and voters safe. Paul wrote that book, and he has rightfully been recognized across our nation for creating a model on how to protect our critical elections infrastructure while preserving Americans’ First Amendment rights to peacefully protest. As he prepares to step down from his position, I join election officials across Arizona in saying that we will miss his steady hand in times of crisis. But mostly, I want to congratulate him on a job well done.”
Mitchell said she and the sheriff enjoyed “a great working relationship with a shared focus on protecting and keeping Maricopa County safe."
Statement from County Attorney @Rachel1Mitchell on Sheriff Penzone's Announcement: “In my tenure as County Attorney, Sheriff Paul Penzone and I have had a great working relationship with a shared focus on protecting and keeping Maricopa County safe." (1/3) pic.twitter.com/tuH6d5Hx52
— Maricopa County Attorney's Office (@marcoattorney) October 3, 2023
Gallego called Penzone a friend and credited him with modernizing county jails.
I’m grateful for Sheriff Penzone’s friendship, his work to modernize the county’s jails and his partnership to reduce recidivism in our criminal justice system. He’s always acted with integrity and has been an exemplary public servant. I wish him the very best in the future. https://t.co/7ONRWq4n2f
— Mayor Kate Gallego (@MayorGallego) October 2, 2023

Penzone inherited Arpaio’s legal troubles
Penzone will leave behind a 16-year-old court case that dates back to Arpaio’s reign.The class-action lawsuit, Melendres v. Arpaio, took Arpaio to court for his racial profiling practices. Although it led to his criminal contempt conviction in 2017, a pardon from former President Donald Trump ultimately let him off the hook.
Penzone inherited the lawsuit when he took office in January 2017. In November 2022, U.S. District Court Judge Murray Snow held Penzone in contempt in the case. According to Snow, the massive backlog of misconduct investigations had swelled during Penzone’s tenure, and it took the agency an average of 611 days to look into a complaint — far beyond the 85-day limit imposed under Snow's court order.
Understaffing at the Professional Standards Bureau, the sheriff's internal affairs division, made it hard to meet the 85-day mandate. As a result, Penzone asked the Maricopa County Board of Supervisors in December for approval to pay more than $1.15 million in fines.
Penzone also appealed the judge’s ruling in January.
According to the court pleadings, Penzone said he managed to fully staff the bureau and could likely meet the judge's demands — just not within the rigid time limit.
The case triggered tensions with the Community Advisory Board, an independent five-person panel created to review policies at the sheriff's office and open dialogue between it and the public. In February, board members publicly expressed "outrage" over the agency's failure to comply with court orders.
Sylvia Herrera, a member of the Community Advisory Board, criticized Penzone in June for appealing the judge’s ruling.
"There was always reluctance on all aspects of the order, I think," Herrera told New Times in June. "They don't want to be monitored by the court monitor. They don't want to be held accountable."
Yet Penzone’s hiring efforts allowed him to skirt the hefty fines Snow threatened to impose.
In May, Robert Warshaw, an independent monitor appointed by Snow to oversee compliance by the sheriff’s office, expressed his disappointment in the investigation’s progress.
"The time it takes to conduct and close investigations remains unacceptable, and it is the agency that bears the responsibility to address this issue," Warshaw wrote in a report on MCSO's progress.
On Monday, Penzone lamented the ongoing federal court oversight of the sheriff’s office. The compliance efforts, he said, have “literally depleted a considerable amount of the resources in this office that could and should be dedicated to public safety.”
“I leave with opportunities in front of me. I’m not running from a fight because I never have and I never will,” Penzone added. “But I do recognize this: I’ll be damned if I’ll do three terms under federal court oversight for a debt I never incurred and not be given the chance to serve this community in the manner that I could if you take the other hand from being tied around my back.”
Additional reporting by Matt Hennie, Serena O'Sullivan and O'Hara Shipe.