(Bloomberg) — President Joe Biden has settled on former Chicago Mayor Rahm Emanuel as his ambassador to Japan, according to two people familiar with the matter.

Emanuel, 61, represented Chicago in the U.S. House from 2003-2009, serving as Democratic caucus chairman and head of the Democratic Congressional Campaign Committee, before leaving Congress to become Barack Obama’s first White House chief of staff.

As DCCC chairman, Emanuel captained Democrats’ successful bid to retake the House majority in 2006. He also served as a senior adviser to President Bill Clinton.

Emanuel’s political pedigree and combative personality could make his nomination — which is subject to Senate confirmation — contentious. He’s been considered for various administration roles since Biden’s November election victory.

He was said to be a contender for transportation secretary, a position that went to Pete Buttigieg.

Progressives have raised concerns about Emanuel’s record in the Obama administration, particularly his opposition to a larger stimulus bill in 2009 and what they see as an unwillingness to work with the left. Some groups, including the NAACP, have said that his handling of the police killing of 17-year-old Laquan McDonald in Chicago should disqualify him from the Biden administration.

The Financial Times first reported Biden had chosen Emanuel for the post.

The White House hasn’t yet publicly announced nominees for ambassadorships to Japan or China as Biden recalibrates the U.S. presence in Asia after the Trump years.

Former Under Secretary of State for Political Affairs Nicholas Burns is among the top choices to lead the embassy in Beijing.

Biden is looking to fill the posts as he seeks to enlist allies to vie with China on issues ranging from the production of semiconductors to freedom of navigation in the South China Sea to human rights abuses in Xinjiang. The president has predicted “extreme competition” with the Asian superpower in the years to come.