Longtime Washington powerhouse lawyer Greg Craig, whose past clients include a president and a man who tried to assassinate one, is now representing former Alabama Gov. Don Siegelman.

Craig, who was President Obama's White House counsel from 2009-20010, and his law firm have taken over Siegelman’s appeal of a 2006 bribery conviction. 

Siegelman confirmed, in a letter to a Fox News producer, that Craig had taken over his appeal seeking a new trial. In the letter, Siegelman said he and Craig, who have known each other since 1967, met at the prison about a month ago. 

"He left with a different view of my legal chances," Siegelman wrote, adding: "If I get out and still am considered guilty of something I know didn't happen I'll spend the rest of my life fighting for the truth to come out." 

The ex-governor's longtime attorney, Peter Sissman, withdrew from the case because of an illness, according to a local newspaper report. According to Siegelman, Craig initially came on board to help advise on his commutation request -- before the president Craig used to work for. 

FoxNews.com was unable to reach Craig for comment.

Siegelman is just the latest to join the roster of high-profile clients Craig has represented. The attorney first rose to prominence in 1981, when he was part of the legal team defending John Hinckley Jr. in the attempted assassination of President Ronald Reagan. Hinckley was found not guilty by reason of insanity.

Craig later served as Sen. Ted Kennedy’s senior adviser on defense, foreign policy and national security issues from 1984-1988, and represented Kennedy in 1991 in connection with the rape trial of his nephew, William Kennedy Smith.

President Bill Clinton appointed Craig as assistant to the president and special counsel in 1998, and the Yale Law-trained attorney led the president's legal team during impeachment proceedings.

Since resigning from the Obama administration, Craig has worked at Skadden, Arps, Slate, Meagher and Flom. 

Fox Business Network's Eric Spinato contributed to this report