Mr. Jackson, who is single, is a native of Butler County, Ohio, and attended the University of Iowa, where he was drawn to politics, becoming Iowa’s youngest Republican county chairman at 25. In 1990, he signed on with Mr. Boehner, who was about to begin a House campaign, and went with him to Washington the next year. He stayed for the next decade and helped build what some people call “Boehner Land.”

He signed on with George W. Bush’s presidential campaign and organized the Barnstorm for Reform tour, where Republican governors fanned out across the country to campaign for Mr. Bush. He helped manage the 2000 Republican convention in Philadelphia and joined the Bush White House as a deputy to Mr. Rove. In 2007, he took over most of Mr. Rove’s portfolio when Mr. Rove left the White House.

Friends talk about his “serious chef’s kitchen” and the “top-shelf” meals he served on a sailing trip to the British Virgin Islands.