Healey, who will be sworn in at the State House midday, also has less than two months to submit her first state budget to the Legislature, while also finishing staffing her administration, with notable leadership roles in housing and public safety still open.

And while Healey has broadly identified her administration’s priorities, she must now lay out in greater detail how she intends to tackle them.

But unlike outgoing Governor Charlie Baker, Healey, a Democrat, has the advantage of partisan alignment with legislative leaders. And she’s made the transition from campaigning to serving in office before, learning valuable lessons from doing so, said Shannon Jenkins, a professor of political science at the University of Massachusetts Dartmouth.

“When you’re attorney general, people work for you. As governor, you have to work with the Legislature,” Jenkins said. “I think that will be one of her biggest challenges.”

Here’s a look at some of the tests awaiting Healey:

Healey assumes power as the Massachusetts Bay Transportation Authority is responding to a long list of new mandates from federal safety officials while still struggling with a deep shortage of workers and persistent delays. She has also promised to provide more transparency on safety matters, and has committed to hiring a transportation safety chief to audit the entire system.

She also inherits a large portfolio of ongoing projects, including the expansion of rail service between Boston and Western Massachusetts, and the Red-Blue line Connector, and will work with federal authorities to replace the two aging bridges to Cape Cod.

“She needs to be able to catch up while expanding the systems,” said Stacy Thompson, the executive director of LivableStreets Alliance. “We have to keep the state moving, literally.”

To pay for those improvements, Healey should have the boon of new revenue: the “millionaire’s tax,” which will be applied to annual incomes over $1 million and is designed to fund education and transportation, is estimated to bring in $1.2 billion to more than $2 billion annually. But the ballot measure does not guarantee the Legislature will actually increase spending overall in those areas.

“A lot of people in the transportation community are concerned about making sure that there is a fair distribution of the resources,” said Thomas Glynn, a former general manager of the T and chief executive of Massport.

In the coming decades, scientists say, climate change threatens both property and public health in the state, from devastating flooding inland, to oppressive summers, to hundreds of new cases of asthma. It is past time for major action from local, state, and federal leaders, experts agree.

Under Baker, Massachusetts laid out a plan for the state to reach net-zero emissions by 2050. But it now falls to Healey to get there. Her administration must implement a major new climate law that will speed the state’s transition to clean energy and allow some cities and towns to ban the use of fossil fuels in new construction.

“They come in with a framework in place, but a lot of details to be fleshed out — and quite frankly, some of the tougher details to be fleshed out,” said Ben Downing, a former state senator who serves on Healey’s transition committee on climate. “We have the ability to meet this moment. But the leadership required for that is going to have to be constant and it’s going to have to have a sense of urgency.”

It’s also crucial that Healey and her team keep in mind the disadvantaged communities that are most vulnerable to climate change, said Roseann Bongiovanni, executive director of the Chelsea environmental justice organization GreenRoots.

“How do you make sure that the voices of those communities are heard prominently?” Bongiovanni said. “It’s more than a ‘check the box.’ It’s about actually being inclusive and intentional.”

As state residents continue to feel the squeeze of inflation, Healey has said she will improve affordability and push the Legislature to revisit tax-relief legislation that was lost in the chaos of last year’s formal session.

Experts say she will be challenged by a financial environment in which the state’s surplus seems larger than it is. A 40-year-old law required $3 billion be sent back to taxpayers last year, and now the state faces the impending expiration of federal dollars from coronavirus aid legislation that must be spent in the next few years.

“There are a lot of expectations and receding revenues,” said Phineas Baxandall, a senior analyst at the left-leaning Massachusetts Budget and Policy Center.

He said his group hopes Healey continues to advance some of the progressive policies she pitched on the campaign trail, such as a $400 million plan to expand state tax credits for children and other dependents.

Her proposal would combine two existing tax credits into one and more than double the award, be indexed to inflation, and be written into the state’s tax code, instead of being funded by the Legislature on a yearly basis as other tax credit programs are.

However, it will take buy-in from the Legislature and a carefully balanced spending plan.

“It’s going to be a challenge,” Baxandall said.

Rent and home prices seem to go in only one direction in Massachusetts: ever higher. Advocates agree that the state is short hundreds of thousands of housing units, with the high cost of living threatening the state’s workforce and economic competitiveness.

“This is a huge challenge for anyone,” said Josh Zakim, a former Boston city councilor and executive director of Housing Forward-MA, but “our incoming governor and lieutenant governor are up for the task.”

One early task: implementing a major new law that mandates communities adopt new multifamily zoning in areas served by the MBTA — “the biggest zoning change we have had in more than 40 years,” according to Rachel Heller, executive director of the advocacy group Citizens’ Housing and Planning Association.

By the end of January, 175 communities with MBTA stations must submit plans for complying with the law. That leaves little time, as the new administration will need to help local authorities shape those plans and come down on those that fail to, including by withholding state funds. Desperately needed housing production in pricey Eastern Massachusetts depends on the law, advocates said.

The Healey administration will also likely need to file a new housing bond bill this year, which is typically passed every five years and used to finance affordable housing production, tax credits, and other programs. Advocates warn that Healey’s team needs to move quickly because the $1.8 billion authorized by the 2018 bond bill could soon run dry.

“We cannot miss a beat when it comes to investing in affordable housing right now,” Heller said.

Meanwhile, another familiar threat looms again: COVID-19 hospitalizations are on the rise, and the state is battling a new variant, XBB, that experts say evades immunity better than earlier strains.

Julia Raifman, a Boston University public health professor, said Healey should focus on boosting vaccination rates and testing availability in underserved communities, deciding when masking protocols may need to be resumed in schools and workplaces, and remedying health care worker shortages.

The challenges, however, go beyond the infection and response. Pandemic-related federal programs that funded housing, food, and access to health care for the state’s neediest residents have expired.

“The instability that [the pandemic] is creating in people’s daily lives . . . is really critical,” said Carlene Pavlos, the executive director of the Massachusetts Public Health Association.