DeFeo managed the digital side for former President George W. Bush's reelection campaign and the RNC's digital efforts in the 2002 campaign cycle.
He will work alongside Andy Barkett, who joined the RNC from Facebook in June to serve as its chief technology officer.
"Chuck is a true digital pioneer who will bring a wealth of experience to the RNC," Priebus said in a statement. "He will join CTO Andy Barkett in revolutionizing the way the RNC approaches data, digital and technology. His experience on campaigns, in government and with grassroots advocacy, and in new media will be invaluable."