A source says Coffin is expected to take a breather from the rapid pace of government service to spend time with his wife and two small children before returning to private practice after New Year's.
Reached by phone at his office, Coffin declined comment and referred calls to the public relations office.
Coffin joined Cheney's staff in 2005 to fill the position once held by David Addington, who replaced Lewis "Scooter" Libby as chief of staff after his indictment. In that capacity, Coffin has served as the top legal adviser to the vice president.
The Cheney assignment was Coffin's second stint in the Bush administration. Until mid-2004, he served as deputy assistant attorney general in the civil division. It was there that Coffin first won favor with Cheney when he successfully defended the vice president from having to publicly release documents related to his energy task force.
Coffin also led the government's effort to bar frozen Iraqi assets from being used to pay an award to prisoners of war from the Gulf War. And he headed up the Justice Department's defense in cases challenging so-called partial-birth abortions.
By Emma Schwartz