She bagged the Humboldt Park alligator, humiliated her indicted nemesis on the Chicago City Council floor and began chipping away at aldermanic prerogative.

She cleaned house at the Board of Education, scored a Chicago casino that can’t be financed and delivered ethics reform and predictable scheduling but also rained on her own parade with an open-mic putdown of a police union leader.

On Wednesday, Mayor Lori Lightfoot marks 100 days in office.

That’s one day before she will confront a billion-dollar-plus shortfall that could bring her political honeymoon to an end.

Lightfoot is off to a whirlwind start fit for a former federal prosecutor who owes her landslide victory to a still-unfolding corruption scandal.

What stands out so far is her resolve to be the “anti-Rahm” — collaborating more, dictating less, taking steps to rebuild neglected neighborhoods on the South Side and West Side and reforming the city council and also a ticketing-and-booting policy that has punished minority drivers, pushing some into bankruptcy.

Analysis

That’s even though she has retained a surprising number of former Mayor Rahm Emanuel’s department heads and agency chiefs.

Also noteworthy — and more problematic — is Lightfoot’s struggle to rein in violent crime, her controlling demeanor and propensity to take things personally and get even. In that way, she is very much like Emanuel.

Two prime examples involve the Fraternal Order of Police: repeating a “rumor” that the FOP instructed members to “lay back” over Memorial Day weekend and getting caught on an open microphone referring to a police union official as “this FOP clown.” She apologized — but only for saying it out loud.

There have been others, too. Lightfoot’s feud with vanquished mayoral challenger Toni Preckwinkle. Her sexism claim against a community activist alarmed by the unsolved killings of 75 South Side women. Her decision to banish 20-year Ald. Anthony Beale (9th) from her leadership team for opposing Finance Chairman Scott Waguespack (32nd).

“Her single biggest flaw is that she is hypersensitive and thin-skinned,” says a mayoral confidante speaking on the condition of not being named. “If she’s ever going to be undone, that’ll be her undoing.”

Waguespack says Lightfoot is “very tough-minded. … That’s pretty obvious from her calling people out at the council meetings.”

He says the new mayor is “just laying down her markers that voters wanted for quite a few years.. ... The people who are upset are the people who’ve been gaming the system for too long.”

On the day earlier this month that she accepted the resignation of Marielle Sainvilus, her first communications director, Lightfoot said the coming 100-day benchmark “feels a little bit like a Hallmark holiday” because she’s “looking at four years.”

She said her administration has “done a lot in a relatively short period of time” by “being out in the communities, being willing to listen and bring people into the conversation and …along [on] the journey.

“It’s really important for us to have set the style of governance and the way in which we want to engage with residents and stakeholders. ... We can’t ask people to support us if we’re not present and there for them.

“I keep going to places where people say to me, ‘I’ve never met a mayor before. I’ve never seen a mayor here. I’ve never seen a mayor do this.’ In some ways, that’s heartening. But it’s also heartbreaking.”

It’s been clear since her inauguration that Chicago’s first African American female mayor and the first openly gay mayor would be a different kind of leader. After triumphantly declaring “reform is here,” Lightfoot turned her back to the Wintrust Arena crowd to face the aldermen she had just portrayed as corrupt and insisted they join the cheering masses in a standing ovation for council reform.

That same day, she signed an executive order stripping aldermen of their control over licensing and permitting powers in their wards. She has promised to do the same for aldermanic prerogative over zoning, though that would require a council vote.

In a bizarre moment 10 days later, having presided over her first council meeting and installed her new council leadership team, Lightfoot seized a chance to humiliate Ald. Edward Burke (14th), gloating about her triumph over a pathetic-looking Burke.

The following day, Burke was hit with a 14-count racketeering and extortion indictment that accuses him of using his governmental role to muscle business for his law firm.

Lightfoot’s repeated demands for Burke’s resignation were ignored. But her hand was strengthened, and she’s played it to the hilt. She convinced aldermen to restrict their outside income and grant sweeping new investigative powers to City Hall Inspector General Joe Ferguson.

Three years ago, Burke and Ald. Carrie Austin (34th) — the deposed council budget committee chair whose ward office was raided by the FBI in June — thwarted efforts to give Ferguson greater authority.

The ethics reform and predictable scheduling ordinances were an easy bone to throw to progressives. It will be harder to keep them happy long term.

Lightfoot faces pressure from the political left on issues including affordable housing, civilian police review, moving to an elected school board, the Chicago Police Department’s error-filled gang database, a community benefits agreement to protect residents living around the planned Obama Presidential Center and raising Chicago’s minimum wage to $15 an hour more quickly than the state.

A former Chicago Police Board president, Lightfoot also angered some progressives by promising to make the $95 million police and fire training academy in West Garfield Park bigger, better and undoubtedly more expensive. That made the anti-Rahm look like anything but.

Lightfoot appeared to have won a shortfall-reducing jackpot when the Democratic-controlled legislature approved the casino that has eluded Chicago mayors for decades. But an Illinois Gaming Board consultant has since concluded the taxes the deal calls for are so high that not even a casino located in or near downtown would attract financing.

“I would hope that nobody underestimates me ever, but we’ll see,” the mayor said the day the report was released. “I’m the new kid on the block. And look, I’m learning. Just as they are learning about me, I’m learning about them.”

Now, Lightfoot needs a casino gambling fix during a fall legislative veto session during which she also will seek state authorization to raise Chicago’s real estate transfer tax and impose a new tax on professional services. That’s after stumbling by floating a plan to have the state take over the city’s $28 billion pension liability that Gov. J.B. Pritzker predictably shot down.

Even if Lightfoot gets other state help, she will be hard-pressed to avoid another increase in property taxes, which doubled under Emanuel.

She’ll also be forced to do serious cost-cutting and possibly to resurrect a smaller version of Emanuel’s proposed, $10 billion pension borrowing.

And she might have to risk a confrontation with the Chicago Firefighters Union Local 2, which gave her a key endorsement. She could take aim at perks that pad firefighter paychecks, costing millions.

Lightfoot’s proposed budget solutions are certain to face resistance from aldermen whose powers she has diminished. No wonder the mayor has created a political action committee to scare off opponents.

“When aldermen are asked to take some really tough votes on really tough issues — and they get heat from their constituents — there’s gonna be no reservoir of goodwill that they feel toward her,” says a former alderman who spoke on the condition of remaining anonymous.

That former alderman says Emanuel worked to build “real loyalty” among his council majority. Aldermen “really felt that he had their back,” the former council member says. “I don’t think there’s anyone in the city council who feels that Lori Lightfoot has their back.”

Another test that awaits Lightfoot will be whether she can deliver a new teachers’ contract without a strike. With the Chicago Public Schools on more solid financial footing thanks to a state funding windfall secured by Emanuel, Lightfoot made a $300 million offer to the Chicago Teachers Union — whose list of contract demands would cost $2 billion.

She sweetened the pot, filling the school budget with goodies and promised a five-year plan to hire more nurses, social workers, librarians and other support personnel. The CTU wants it all in writing.

Lightfoot is more likely than not to deliver on her “not on my watch” promise to avoid a second teachers strike in seven years by a union that was among Preckwinkle’s biggest supporters. A fact-finder already has sided with the mayor.

Meanwhile, negotiations with a police union with whom Lightfoot has been at war appear headed to arbitration as the struggle to rein in violent crime drags on.

In her inaugural address, Lightfoot declared there is “no higher calling than restoring safety and peace in our neighborhoods.”

But the numbingly familiar drum of violence dominating nearly every summer weekend in Chicago shows how difficult it will be to deliver on that promise. Lightfoot recently admitted as much, saying, “It feels like we’re losing the streets.”

Remarks like that have fueled speculation that police Supt. Eddie Johnson won’t make it to April, when his superintendent’s pension is fully vested. Johnson could tire of being called out by Lightfoot at weekly “accountability” sessions. Or Lightfoot could get fed up and pull the plug.

After “flooding the zone” over Memorial Day weekend with 1,200 more cops and 100 events and youth programs, Lightfoot came away with results sadly similar to previous years. That prompted her to tie Chicago’s cycle of gang violence to “systemic disinvestment” in South Side and West Side neighborhoods.

She has since imported a respected city planner from Detroit, Maurice Cox, and appointed a chief equity officer, Candace Moore, as well as deputy mayors for public safety, neighborhood and economic development, education and infrastructure. All must now deliver the “transformative” investments Lightfoot has promised in neighborhoods that haven’t seen it in decades, starting with “high-priority commercial corridors.”

The bottom line for the new mayor is much as it always is when politicians are judged after their first 100 days. Lightfoot is a work in progress. And the toughest work that will define her tenure and determine her political future lies ahead.