Ronal Serpas is out as police chief in New Orleans.

After four often-rocky years on the job, Serpas announced his retirement as New Orleans police superintendent Monday.

Serpas said at an 11 a.m. news conference that he plans to stay in the city for a new job, but would not say what it was. Sources say the chief has landed a tenured position at Loyola University.

Lt. Michael Harrison, police commander of the 7th District, which covers almost all of New Orleans East, will serve as interim NOPD superintendent.

The announcement was sudden, but shouts for Serpas’ resignation punctuated much of his tenure. The loudest came from police officer groups embittered about several issues, including reforms to the off-duty detail system and a stiff disciplinary regime that led to the termination of scores of cops on grounds that many viewed as specious or arbitrary. Serpas, the chorus went, never had their backs.

As recently as last week, newly elected City Councilman Jason Williams suggested in a little-noticed web broadcast that at least five members of the council were prepared to terminate Serpas — a power bestowed by the city charter but never before exercised.

In recent months, Mayor Mitch Landrieu’s support for Serpas appeared tepid. The normally loquacious mayor took to answering questions about his police chief with a terse, one-word affirmation, even as Landrieu’s challengers called for Serpas’ head.

Rumors that the chief was job hunting circulated regularly — and sometimes appeared to have legs, though he repeatedly said he was going nowhere. Officials in Miami Beach, Fla., for instance, appear to have at least briefly considered Serpas amid a search to replace the retiring police chief there, according to city emails, though it’s unclear whether Serpas was ever interested in the job or even aware that his name had been mentioned.

His departure marks the latest new beginning in a career that began humbly enough, as a beat cop who had to earn a GED after dropping out of Abramson High School, and eventually took him to the NOPD’s No. 2 spot, by which time he had a Ph.D. As deputy chief, he was a key aide to reformist Police Superintendent Richard Pennington; he left the city in 2001 to assume the top spot in the Washington State Patrol. Three years later, he assumed the job of police chief in Nashville, Tenn., before coming back to New Orleans in 2010 with a mandate to reform and rebuild the city’s beleaguered force, by then badly tarnished by misconduct cases and facing the prospect of a federal consent decree requiring various changes to police training and practice.

That consent decree came in the summer of 2012, leaving Serpas — a self-described “change agent” — at the helm of a department under the yoke of the most wide-ranging and demanding blueprint for police reform in the nation. By then, Landrieu, who initially welcomed the Justice Department into NOPD with open arms, had changed his tune, resisting aspects of the consent decree as expensive and unnecessary.

Serpas’ watch has been marked by a dramatic decline in its notorious murder rate — a slide for which much of the credit has gone to a wider, Landrieu-led anti-violence campaign. Homicides fell by nearly 20 percent last year; the 156 murders recorded were fewer than New Orleans had seen in decades. On a per-capita basis, the city for the last two years has been less murderous than Detroit and Flint, Mich.

Yet Serpas leaves a department with badly depleted ranks, thanks in part to a years-long hiring freeze imposed by Landrieu. An upstart recruiting campaign has been unable to hire new officers as quickly as the old ones are leaving. The force is now more than 400 officers lighter — a nearly 30 percent decline from pre-Katrina levels — leading to slower police response times and often woefully undermanned district stations.

By most accounts, morale is low, with the rank-and-file grousing about everything from the new, federally imposed rules on private detail work to the continuing perception that politics still runs deep in departmental decision-making.

Controversy has surrounded Serpas from the beginning, when some critics labeled Landrieu’s nationwide police search a sham in which Serpas always had the inside track. Four members of a panel Landrieu created to screen candidates for the job either resigned or were removed after complaining about a lack of transparency. During the search, Serpas had the strong backing of many business leaders, and Landrieu interviewed only one other candidate personally before choosing him.

The city even took heat about Serpas’ start date, as questions swirled about whether he backdated a sworn document to meet a deadline for picking up retirement benefits.

The critics have never fully quieted down, with Serpas taking steady heat for everything from a perceived lack of progress in reducing violent crime — and questions over proper recording of crimes — to the NOPD’s sometimes aggressive tactics.

Over the course of one week in 2012, police shot and killed two young African-American men, one during a traffic stop and the other during a drug raid. The latter shooting, which claimed the life of Wendell Allen, 20, eventually prompted charges against Officer Joshua Colclough, who is serving a four-year prison term after pleading guilty to manslaughter.

The incidents prompted renewed calls for Serpas to step down, calls that were especially loud in the black community.

Questions about the reliability of the crime statistics the NOPD reports to the public and the FBI have dogged the department during Serpas’ tenure, with Inspector General Ed Quatrevaux taking aim in one report at the department’s repeated misclassification of thefts in the French Quarter as “lost or stolen property.” Serpas, who also faced questions of stat-fluffing in Nashville, has strongly denied any concerted effort to rig the books, saying any mistakes were honest ones.

Serpas faced some of his harshest criticism in 2011, when it emerged that Police Commander Edwin Hosli — one of Serpas’ closest friends on the force, who had the prestigious position of overseeing the French Quarter-based 8th District — had set up a limited liability company for a side gig in which he and other officers were paid extra by the city to review traffic-camera tickets. The practice violated NOPD policy, and the news of the arrangement broke as Serpas was starting to embark on a controversial overhaul of private detail work.

Amid the controversy, Landrieu himself stepped in and suspended Hosli, a rare instance in which the mayor seemed to undercut the chief’s authority.

The Hosli matter raised questions about internal politics in a department that has long been factionalized. While Serpas has at times been an unsparing disciplinarian – touting a new “you lie, you die” policy over police misconduct — there was no rush to judgment in the Hosli case. Though Hosli was removed from his 8th District command, he was eventually restored to a leadership post, and he retired from the force in June for a high-ranking job with the sheriff’s office. His treatment differed starkly from that afforded to a group of seven captains and a major who fell out of favor with Serpas and were assigned to a newly created “Administrative Support Unit” based in a FEMA trailer in City Park.

That group recently won a ruling from the Civil Service Commission saying that the menial work the department has given them is essentially beneath them.

Landrieu’s feelings about Serpas have been hard to read at times. He has resisted the nearly continuous calls over the years for Serpas’ resignation emanating from activists and politicians — most prominently, perhaps, Landrieu’s chief opponent in this year’s mayoral election, Michael Bagneris, whose central campaign plank was firing Serpas.

But Landrieu was rarely a full-throated defender of his top cop, either. Notably, in a nearly two-hour interview with the New Orleans Advocate in June, during which he waxed at length extemporaneously on a smorgasbord of topics, he gave a clipped, one-word answer — “yes” — when asked if he had confidence in Serpas.

And while Bagneris didn’t mount much of a challenge to Landrieu, several of the new members elected to the City Council this year campaigned in part on anti-Serpas themes. One of them, at-large member Jason Williams, said in a webcast last week that he believed Serpas had worn out his welcome — and added that he thought he had the votes to send him packing. During a conversation recorded as a part of an online radio program called “Happy Hour,” Williams said that he thinks the city as a whole is running out of patience.

“I think we need a change in leadership,” Williams said, citing NOPD’s manpower shortage, as well as the continuing scourge of gun violence and other crimes.

In that interview, Williams portrayed Landrieu as unswerving in his support for Serpas.

Members of the City Council, he said, “see it differently. We did not hire him. We’re not pleased with the performance, so with five votes we can make a change.”

It wasn’t clear whether Williams was making an idle threat or not. It’s never been done before, but the council technically can terminate a department head, though it would involve a cumbersome set of parliamentary procedures, akin to an impeachment. The city’s charter says the council can “bring charges” against top mayoral appointees for “lack of qualifications, incompetence, neglect of duty, failure to comply with a lawful directive of the Civil Service Commission or gross misconduct.”

If Serpas leaves policing altogether, he may lose his place in line to assume the presidency of the International Association of Police Chiefs, which was expected to occur in October 2015. He is currently the organization’s second vice president.

Serpas had already ensured himself a maxed-out retirement package in New Orleans when he marked three years as chief, a milestone he hit in May 2013. Pension benefits are calculated on the basis of years of service and the average of a worker’s three highest-salaried years. Because of Serpas’ earlier tour of duty with NOPD, he already has enough years on the force to receive a full pension.

Serpas’ four-year run at the NOPD’s top position is a fairly typical tenure for the job, often considered the city’s most important – and most impossible. His predecessor, Warren Riley, served as chief for five years after having taken over for Superintendent Eddie Compass weeks after Hurricane Katrina laid waste to the city, and did irreparable damage to the police force. Compass, who was Mayor Ray Nagin’s initial choice for the job, served three years in the job. He was preceded by Pennington, who served as chief for all eight of Marc Morial’s years as mayor.