Cochrane, who recently returned from maternity leave, will continue to run on- and off-air marketing for Channel 4.
She will add to this responsibility for the channel's commercial arm, 4 Ventures, which is separate from its public service terrestrial activities.
Cochrane will report to 4 Ventures managing director Rob Woodward about commercial development and will continue to report to David Brook, Channel 4 director of strategy and development, on matters of brand and marketing strategy.
Bill Griffin has replaced Cochrane as head of marketing, while Lisa Green has been promoted to head of 4Creative. Both will report to Cochrane.