Barbour and campaign officials confirmed the hire, which was first reported by Politico.
During the 2012 race, Barbour was a deputy to top Romney adviser Stuart Stevens and helped with fundraising and get-out-the-vote efforts in early states. More recently, he was credited with reviving Sen. Thad Cochran's 2014 reelection campaign as it faced a strong challenge from Chris McDaniel.
He is the brother of Henry Barbour, another active but so-far unaligned GOP operative — and the brothers are nephews of former Mississippi governor Haley Barbour, a former chairman of the Republican National Committee.
Barbour's hiring comes as top Bush donors are warning that the former Florida governor needs to demonstrate growth in the polls over the next month or face serious defections among supporters.
As The Washington Post reported Monday, Sen. Marco Rubio (R-Fla.) appears to be gaining momentum among former top donors to Wisconsin Gov. Scott Walker, who dropped out of the GOP presidential race last week. At least a third of the bundlers who signed up to raise money for Walker have switched their allegiance to Rubio, while a smaller number have gone with Bush, according to people familiar with the discussions.
But the Bush campaign is starting to have some success among former Walker supporters. In South Carolina, Dave Ellisson, chairman of the state's Club for Growth chapter, and Brenda Earls, a former chairwoman of the Cherokee County GOP, switched allegiance from Walker to Bush on Monday. Ditto Chad Airhart, the Republican recorder of Dallas County, Iowa, who told a local television station that “It’s easy to close your eyes and imagine him to be president."
Such moves don't matter much at the national level, but in the early states — where every single vote makes a difference — wooing local leaders can help bring along dozens, if not hundreds of potential supporters.