The agency's appointment comes as Superdry looks to expand its international sales through an online retail strategy under the head of e-commerce, Chris Griffin.
ICrossing, part of Hearst Corporation, will run the account from its UK offices and will also focus on building web presence in new territories including Scandinavia, South Korea, China and Australia.
Superdry is looking overseas to boost its fortunes. In May, the brand's owner, SuperGroup, posted "flat" underlying UK sales in the 13 weeks to the end of April, after issuing earlier profit warnings.
This week, the Superdry co-founder Theo Karpathios, who helped the chief executive, Julian Dunkerton, launch the brand in 2005, announced he is leaving the company. His departure follows the appointment of new directors, including the chief operating officer, Susanne Given.Follow @Darbs73