Holder, 57, met Obama only four years ago, but the affable Bronx-born son of a Barbados immigrant quickly won a seat in the Democrat's inner circle. If he becomes the next chief U.S. law enforcement officer, Holder will try to win back the public's confidence in the Justice Department - an agency whose fiercely independent image was tarnished by GOP political meddling during the Bush administration.
"Internally, there is a morale problem the likes of which I have never seen before," Holder said in an interview late last year. "Externally, there is a crisis of confidence that the nation has with regard to the department."
Holder's nomination is expected to be formally announced as soon as this week. He has made no public comment on the nomination, though an Obama official and two Democrats in touch with Obama's transition team on Tuesday confirmed that Holder is the top choice for attorney general.
Holder helped lead the team that selected Sen. Joe Biden as Obama's running mate. Throughout his career as a judge, a prosecutor and a defense attorney for the prestigious law firm Covington & Burling, Holder's independence rarely has been questioned. But one of his final acts as President Bill Clinton's deputy attorney general in 2001 could come back to haunt him as he seeks Senate confirmation for the Justice Department's top job.
On the last day of Clinton's term, Holder told the White House he was "neutral, leaning toward favorable" for a presidential pardon for Marc Rich, a wealthy commodities dealer who had spent years running from tax charges. Rich's ex-wife, Denise, was a prominent Democratic Party donor.
It turned out to be a bad call. The pardon provoked howls of protests and a congressional investigation over whether it was politically motivated. Holder later publicly apologized for what he called a snap decision and said he would have advised against it had he paid more attention to the case.
Sen. Arlen Specter of Pennsylvania, top Republican on the Senate Judiciary Committee, which will vote on Holder's nomination, said the pardon "would be a factor to consider."
"I wouldn't want to articulate it among the top items but it's worthwhile to look at," he told reporters Tuesday, adding that it is "too soon for me to say" whether Holder would be a satisfactory attorney general.
Added Sen. Jeff Sessions, a conservative Republican from Alabama: "I like him and I would hope that nothing comes up that would jeopardize his nomination if he were nominated. But he'll have to answer questions and his record will speak for itself."
With Democrats in control of the Senate, however, Holder's confirmation would be virtually assured.
Holder "would make an outstanding nominee, and should have the support of senators from both sides of the aisle if President-elect Obama were to choose him for this critical position," said Senate Judiciary Chairman Patrick Leahy, D-Vt.
Since Obama's election, Holder has privately told colleagues he is concerned the Rich pardon would bloody his nomination hearings and further strain the department's credibility. Still, he is widely respected in legal circles and among Justice Department career lawyers.
In 1988, GOP President Ronald Reagan appointed Holder to the bench in Washington's Superior Court. Six years later, as U.S. attorney in Washington, Holder's office indicted then-Democratic House Ways and Means Chairman Dan Rostenkowski, who ended up pleading guilty in 1996 to mail fraud. And the Senate unanimously confirmed Holder in 1997 for the Justice Department's No. 2 post.
In private practice, Holder represented the NFL in the Justice Department's dogfighting prosecution against Atlanta Falcons quarterback Michael Vick. He brokered a settlement for Merck & Co. Inc. for Medicaid fraud charges brought by five states.
Some of his cases remain in front of the Justice Department. Holder is handling civil case negotiations for the Chiquita International Brands, which claims it was forced to agree to a plea deal and $25 million fine to avoid indictment over security payments the company made to a right-wing Colombian paramilitary group that the U.S. government designated as a terrorist group.
Associated Press writer Ben Evans contributed to this report.