Former Democratic Party chairman Tyler Olson, who is now running for governor, called McCarthy a good leader but said there are others ready to move into the position.
"There are a number of folks with the skills to do the job," Olson said. "We'll have a discussion about who's best to move us forward."
McCarthy, who has a law degree, had worked in the attorney general's office twice between 1994 and 2001. He worked as an executive officer in child support enforcement and consumer protection and as an assistant attorney general in tobacco enforcement.
Attorney General Tom Miller, a Democrat, said he was pleased by McCarthy's return and noted his experience in law, public policy and legislative matters.