Marty Walsh, the two-term mayor of Boston, was confirmed as the Labor secretary by the Senate on Monday, becoming the first union leader to run the department in over four decades.

Walsh will become the head of the Labor Department at a critical time, as the pandemic has left millions unemployed and raised concerns about workplace safety.

The former union leader will also serve in a Biden administration that has pledged to protect the power of unions and is looking to raise the federal minimum wage to $15 an hour.

"Right now, this work is critical to the future of our economy, our communities, and our families," Walsh told senators at his confirmation hearing last month. "I believe we must act with urgency to meet this moment to strengthen and empower our workforce as we rebuild."

Chris Lu, who served as deputy labor secretary under President Obama, said he can't imagine a bigger moment than right now for the department.

The unemployment rate remains above 6 percent and the number of people who have been unemployed for more than six months is at levels not seen since the Great Recession.

And for those in the labor force, workplace safety has become crucial as the country continues to deal with the COVID-19 pandemic. This month, the Labor Department launched a new enforcement program designed to monitor companies where workers are at high-risk for exposure to the coronavirus.

"The Labor secretary is going to be critically important because these issues are going to be front-burner issues for President Biden," Lu said.

Lu added that some key programs at the Labor Department were hollowed out under the Trump Administration. For example, he says the Occupational Health and Safety Administration has the lowest number of inspectors working for it since the 1970s. Walsh pledged to make rebuilding that staff — and other enforcement arms — a top priority.

And although the Labor secretary does not have the power to set the federal minimum wage, Lu said Walsh may be tasked with helping sell it.

An effort to raise the $15 minimum wage was stripped from the latest coronavirus relief package, but the Biden administration says it's committed to finding another avenue to pass it.

"The Labor secretary has an important bully pulpit to make the case for why wages are too low in this country, why it's wrong for people to work full-time and still live in poverty," Lu said.

Meanwhile, issues of equality and discrimination are also likely to be front and center given the Biden administration's focus on racial justice.

"Now is an opportunity to look at how work in the future is going to look like, while also addressing issues of inequality," says Hilda Solis, who served as Labor secretary during the early days of the Great Recession and is now an Los Angeles County supervisor.

The labor department is also now tasked with figuring out what to do with several controversial labor rules written in the twilight of the Trump administration.

One broadened who could be counted as an independent contractor, making it harder for workers in the gig economy to be paid a federal minimum wage or gain access to company-mandated health care. Earlier this month, the Labor Department said it's taking steps to reverse that rule.

Another Trump-era rule would have allowed restaurants to treat some workers like cooks and dishwashers as tipped workers, meaning they could be subject to the sub-minimum federal wage for people who make tips. A decision on whether to implement that rule has been delayed until next month.

The son of Irish immigrants, Walsh grew up in the working-class Dorchester neighborhood and followed his dad into construction. He joined the union, Laborer's Local 223, and worked his way up to eventually lead it.

While preparing for his confirmation hearing in February, Walsh said he thought about family members who belonged to a union.

"I thought about my uncle and my father talking at the kitchen table on Sundays about fighting for the rights of workers, about making sure that jobs were there so that people wouldn't be unemployed," he said.

He also vowed to fight to ensure that people like his family members wouldn't "have to have benefit dances to support union brothers and sisters because their kids were sick or somebody died."

Walsh's personal story is central to his political ascent.

He survived lymphoma as a child, owing his recovery to health coverage fought for and won by the union. In his twenties, Walsh dropped out of college and struggled with alcoholism.

In recovery, he won a seat in the Massachusetts statehouse, where he served 16 years. He took classes at night to earn his college degree. Before he was elected mayor of Boston, he led the Boston Building Trades Council.

Some pro-business groups have been uneasy about Walsh's ties to organized labor, though the U.S. Chamber of Commerce ultimately endorsed his candidacy.

Walsh has also weathered a handful of controversies in Boston leading up to his nomination, including hiring a new police chief who was found to have been the subject of domestic violence allegations. Walsh quickly placed the new chief on leave.

And last month, three community groups filed a federal complaint against the city of Boston for discriminating against Black and Latino-owned firms in awarding contracts.

City Council President Kim Janey will take over as acting mayor. She will be the first person of color to lead the city.