US-born Rona, who left Craik Jones in April without a job to go to, is a former senior vice-president of Digitas London. Before joining Craik Jones in August 2006, Rona worked at Agency.com in New York.
OgilvyOne said Rona would work on a "major global interactive account" but refused to say which one because clients have yet to be informed. The agency's global client roster includes American Express and Unilever.
"We're very lucky to have hired Patrick as very few people are digital experts with an international perspective," said Mike Dodds, managing director, OgilvyOne.
Dodds said the appointment "is a demonstration of the fact that over 50% of our business is digital in terms of briefs. It's also a reflection that big international brands are shifting spend out of traditional advertising into digital media and agencies like ourselves need to have senior, experienced people who are going to help those brands as they make this transition."