President Joe Biden has picked Brendan Danaher, a former Department of Transportation aide and longtime union official, as his new top labor policy adviser.

Danaher joined the White House National Economic Council on Monday as a deputy director, according to a White House official. He replaces Celeste Drake, who left her post this month to join the United Nations’ labor agency.

The appointment comes at a critical time for Biden, who is confronting a series of contentious union negotiations.

The United Auto Workers union is locked in tough contract talks with Detroit’s Big Three automakers, and a work stoppage is possible when their current agreement expires on Sept. 14. In Hollywood, writers and directors are on strike.

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Danaher is one of three White House advisers responsible for labor issues for Biden, who has called himself the most pro-union president in US history and is counting on labor support to help propel him to reelection in 2024.

“Brendan’s deep experience and relationships in government and the labor movement will make him a tremendous asset as the National Economic Council’s Labor Deputy. Brendan will help ensure that working Americans remain at the center of President Biden’s economic policy,” National Economic Council Director Lael Brainard, said in a statement.

Senior Labor Advisor Erika Dinkel-Smith is in charge of labor outreach at the White House Office of Political Strategy and Outreach and senior adviser Gene Sperling is serving as liaison to the UAW and auto manufacturers. They will work closely with Acting Labor Secretary Julie Su on labor issues, the White House official said.

Danaher until last Friday served as labor policy adviser at the Transportation Department, consulting with Secretary Pete Buttigieg on recent labor negotiations critical to supply chains involving freight railroads, West Coast ports and talks between United Parcel Service Inc. and the International Brotherhood of Teamsters. He also served on the administration’s supply-chain task force.

Before joining the Biden administration, Danaher worked for two decades at a number of labor organizations including the AFL-CIO, Transport Workers Union and the American Federation of Government Employees.