Sorokin, who will be based in the US, will head digital on the Unilever account and work alongside the global digital leader Norm Johnston. He reports to Dominic Proctor, the chief executive of Mindshare Worldwide, and starts his position in May.
Sorokin left his role at Carat in October. His departure followed a leaked e-mail indicating Carat's plans to overhaul its US operation and make significant redundancies.
The e-mail, which included a statement from Sorokin, was mistakenly sent to the whole New York agency by Carat's HR department, despite being only intended for the attention of senior managers.
At the time, Sarah Fay, the chief executive of Aegis Media North America, said Sorokin's departure from the agency was "mutual". Sorokin was subsequently replaced by Martin Cass, a former executive vice-president at Carat's US office.