Mary Matalin, Threshold's editor-in-chief, is an old friend of Rove, The New York Times reported, and both worked for President George H.W. Bush. Rove resigned earlier this year as deputy chief of staff.
The Times described Rove's advance as in seven figures, or more than $1 million.
Rove, in a statement, said he would write about Bush's "consequential and contentious administration."
"He's a policy wonk, he's a history buff, he's a reader, he's an accessible intellectual," she said. "So you bring those things together, and I've read every political book out there, and there's nothing close to what he's going to be able to put together."