Webb, who was appointed a non-executive director of the BBC in December 2006, will retain that role, but step down from the Fair Trading committee of the BBC executive.
Mark Thompson, BBC director-general, said Webb's "extensive corporate experience" makes him well-placed to lead BBC Worldwide "through the next stage of its development as a company".
John Smith, chief executive, BBC Worldwide, said Webb's experience at various PLCs "will be invaluable to BBC Worldwide".
Webb was general counsel at British Airways from 1998 to 2009. He is currently chairman of computing firm Autonomy, a non-executive director of the London Stock Exchange and chairman of property developer Argent Group.
Etienne de Villiers was appointed non-executive chairman of the BBC Commercial Holdings Board in 2005 and was subsequently appointed chairman of BBC Worldwide in a restructuring of the BBC's commercial operations in January 2006.
Webb's appointment follows changes to the governance of BBC Worldwide on 17 September, which, among others, led to a decision that the new chairman of the BBC Worldwide board must be a non-executive director from the BBC's executive board.