During his career he has faced controversy -- his involvement in a widely-questioned 11th-hour Clinton pardon and the Elian Gonzalez saga, which occurred during his tenure as the department's second-in-command -- but he also has gained a reputation for having a moderate approach to law enforcement issues and a true dedication to public service.
Holder, 57, met Obama at a 2004 dinner party welcoming the junior U.S. senator from Illinois to Washington, where he was headed to Capitol Hill as the nation's only black senator.
Holder recalled the meeting in a cover story in The American Lawyer earlier this year, saying that he and Obama sat next to each other and "just clicked" after discussing their foreign-born fathers, Ivy League educations and zeal for civil service. Additionally, Holder told The American Lawyer, "I think we share a worldview. ... [Obama] is not defined by his race. He's proud of it, cognizant of the pernicious effect that race has had in our history, but not defined by it."
After keeping in touch over the past several years, Obama asked Holder to formally join his campaign last year. When it came time to form a vice presidential candidate search committee last summer, Holder headed up the effort with Caroline Kennedy.
Holder's resume is packed with Justice Department experience. Straight out of Columbia Law School in 1976, the New York City native joined the department's newly-formed Public Integrity Section, which prosecutes corruption cases.
In 1988, President Reagan nominated Holder to become an Associate Judge for the Washington, D.C., Superior Court. Five years later, President Clinton tapped him to become the first black U.S. attorney for the District of Columbia, which is the largest U.S. attorney office in the country.
Another first came in 1997, when Clinton again reached out to Holder, asking him to serve as deputy attorney general. Holder became the first African-American to hold the position.
But it was during his tenure as the number two at DOJ that the department, helmed by Attorney General Janet Reno, stirred up considerable controversy. Some incidents could haunt a Holder confirmation hearing, though sources tell ABC News that signs are favorable that Holder would be confirmed.
Additionally, Senate Judiciary Chairman Patrick Leahy, D-Vt., whose committee would have the first opportunity to review Holder's nomination before it goes to a full Senate vote, acknowledged in a statement Tuesday that he has known Holder "for many years" and that he "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."
One of the most divisive acts, the pardoning of fugitive financier Marc Rich, came on the last day of Clinton's second term.
Rich had fled prosecution on charges of tax evasion, racketeering, fraud and making illegal trade deals with Iran, taking up residence in Switzerland.
In the frenzied days before the transition of power to the Bush administration, the department reviewed the pardon request, and Holder graded the application "neutral leaning towards favorable."