With Marty Walsh’s Departure, Endorsements Have Piled into Boston’s Mayoral Race. Here’s Who Has Backed Candidates.

Mayor Marty Walsh’s expected, imminent departure for a role in the incoming Biden Administration has blown open Boston’s mayoral race, igniting and stoking speculation about just how diverse the array of candidates could be with the absence of a popular incumbent.

With the shakeup, the only two declared candidates to date, City Councilor At-Large Michelle Wu and District 4 City Councilor Andrea Campbell, have sought in recent days to capitalize on their early forays into the election. Both have rolled out key endorsements, boasting both their broad networks and community roots to set the stage early in what will likely be a turbulent race.

On Saturday, Wu’s campaign unveiled its support from Sen. Elizabeth Warren, the councilor’s former Harvard Law School professor. The high-profile endorsement was followed on Monday with another from the Sunrise Movement Boston, the local chapter of the national grassroots climate justice organization, and on Tuesday with support from OPEIU Local 453 and the Alliance of Unions at the MBTA.

Wu backed Warren early in her run for president in 2019. The city councilor also played a pivotal role in Warren’s own entrance into politics, serving as her campaign’s statewide constituency director when the progressive Democrat took on then-Republican Sen. Scott Brown in 2012.

Wu, in a press release announcing the endorsement, called the senator “a personal hero and friend of mine.”

“Michelle has always been a fighter — as one of my students, as a Boston city councilor, and now as a candidate for mayor,” Warren said in a statement. “She is a tireless advocate for families and communities who feel unseen and unheard. Michelle is not just a woman full of good ideas and a passionate heart, she is a woman who gets out and does the work that needs to be done to make a difference in people’s lives. Bostonians can count on Michelle’s bold, progressive leadership to tackle our biggest challenges, such as recovering from the pandemic, dismantling systemic racism, prioritizing housing justice, revitalizing our transportation infrastructure, and addressing the climate crisis.”

Several of those points, especially Wu’s plan for a “Green New Deal and Just Recovery,” have also earned her praise from the Sunrise Movement, whose endorsement task force voted unanimously to throw its support behind the councilor.

“From building coalitions, to making public transit more accessible to Bostonians, to introducing a comprehensive plan for a Boston Green New Deal and Just Recovery, Councilor Wu has proven herself time and time again to be the type of public servant that is needed leading the city at this moment,” Graham Albert, a member of Sunrise Movement Boston’s political team and endorsement task force, said in a statement. “We are excited to help make her vision for a more inclusive and sustainable Boston a reality by supporting her historic candidacy in the days, weeks, and months ahead.”

And on Tuesday, OPEIU Local 453 and the Alliance of Unions at the MBTA, representing workers in professional, clerical, supervisory, and technical positions, pledged their support to Wu.

“I am proud to stand with the transit workers whose essential service connects our communities and economy,” Wu said in a statement. “OPEIU Local 453 and the Alliance of Unions at the MBTA create opportunities for working families all across the region, and I look forward to continuing to partner on building an equitable recovery to make Boston a city for everyone.”

Last month, Wu earned the support of a dozen elected officials from 11 towns and cities outside Boston, from Pittsfield to Cambridge.

Meanwhile, Campbell on Monday introduced support from a slate of local leaders, including the first elected official in the city to back a candidate in this election. The list highlights the councilor’s community ties, spanning from health care to local activism.

On the list are: Boston Democratic state Rep. Liz Malia; Bill Walczak, former president and CEO of the South End Community Health Center, founder of the Codman Square Health Center, and a former mayoral candidate; Diana Hwang, founder of the Asian American Women’s Political Initiative and a former state senate candidate; Dr. Atyia Martin, founder and CEO of All Aces Inc. and the city’s former chief resilience officer; John Borders IV, a Dorchester community activist and faith leader; and Makeeba McCreary, former chief of staff at Boston Public Schools and a racial equity, philanthropy, and education leader.

“Over the last few years, I’ve seen Andrea demonstrate leadership that is courageous, community-driven, and capable of delivering — not just for her own constituents but for all residents of Boston,” Malia said in a statement. “I am proud to support her as our next mayor of Boston.”

Hwang called Campbell “a rare, authentic leader whose experience and deep sense of justice guide her every single day.”

“As we continue to battle the dual pandemics of COVID-19 and systemic racism in our city, this moment requires a leader who understands the inequities in our communities at her core and who can bring people together across race, ethnicity, and across our neighborhoods to make real change — Andrea is that leader,” Hwang said in a statement.

In December, former Suffolk County sheriff Andrea Cabral also pledged support for Campbell.

Since Walsh officially became President-elect Joe Biden’s pick for secretary of labor last week, Campbell’s campaign says it has received a jolt of support in contributions, raising over $60,000 in the 24 hours following the news. The councilor also released a new campaign ad, underscoring a focus on taking on education, racial, and other disparities and inequities in the city.

Walsh’s pending exit has, of course, set in motion a scramble of other potential candidates, many of them now testing the waters and taking close personal stock of what a run for mayor would entail. Reports have circulated Boston Police Commissioner William Gross is mulling over a possible effort, as well as City Councilor At-Large Michael Flaherty, City Councilor At-Large Annissa Essaibi-George, North End state Rep. Aaron Michlewitz, and South Boston state Sen. Nick Collins, among potentially more.

Should Walsh be confirmed by the Senate, City Council President Kim Janey would take over the reins here in Boston as acting mayor and become the first woman and person of color to serve as the city’s chief executive. Janey has not indicated whether she’ll seek a full term.

As Walsh’s plans to head to Washington, D.C., became clear, Wu’s team immediately set in motion fundraising emails based off the announcement — building off that momentum with additional calls for contributions in the wake of the Warren endorsement.

The subject line in one such dispatch to supporters Tuesday afternoon put it simply: “Full steam ahead.”