Updated at 8:10 p.m. ET

President-elect Joe Biden is tapping Boston Mayor Marty Walsh, a Biden ally with deep ties to unions, as his labor secretary.

The Democrat campaigned for the White House saying he'd be the "most pro-union president you've ever seen."

In a statement Thursday evening announcing the decision, Biden's transition team said that if Walsh is confirmed by the Senate, he'd be "the first union member to serve in this role in nearly half a century."

"Mayor Walsh has the necessary experience, relationships, and the trust of the President-elect to help workers recover from this historic economic downturn and usher in a new era of worker power," the statement added.

In picking Walsh, a white man, the president-elect moves ahead despite some advocates hoping he'd choose a candidate to head the Labor Department who would bring diversity to the Cabinet.

Politico first reported Biden's pick Thursday.

His former primary rival, Sen. Bernie Sanders of Vermont, also expressed interest in the role.

Biden and Walsh have been close for years. They appeared together in Boston in 2019 in support of striking grocery workers, and Biden presided over Walsh's inauguration in early 2018 after his reelection.

Before being elected mayor in 2013, Walsh, a native of the city with a notable Boston accent, was a state representative and head of the Boston Building Trades Council, a union group.

The two Democratic U.S. senators from Massachusetts lauded the pick, with Sen. Elizabeth Warren writing on Twitter that Walsh "is a champion for America's labor unions and a fierce fighter for working families."

Walsh's nomination will be considered by the Senate, soon to be controlled by Democrats, after the party swept both runoff elections this week in Georgia.

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