Sambrook, who has spent 30 years at the BBC, will join the independent PR firm as its first global vice chairman and chief content officer in May.
He will be based in London and will help Edelman clients, which include Heineken, Nike and Unilever, produce words, video and audio content. Sambrook will report to EMEA President and CEO David Brain and will also sit on the global executive committee, chaired by Richard Edelman.
Edelman said it had hired Sambrook because of his experience of launching channels like BBC News 24 and BBC Arabic and his understanding of the audience's role in shaping content.
Edelman said: "Through his work establishing several BBC News channels and his own long-term and personal commitment to social media, he understands very well how the audience is now – to use his own words – 'on the pitch', how content and news must be shaped by the needs of the consumer, and the new opportunities provided by social technologies."
Brain said the fragmentation and decline of many traditional forms of media now means every company needs to become its own media company.
He said: "It has to tell its own story and in ways that people can easily engage with, share and shape. That's sometimes easier to say than it is to do.
"In Richard we now have one of the world's most accomplished creators and managers of content to help our clients do just this."
As part of his role Sambrook will assume leadership of Edelman's global crisis and issues practice towards the end of the year as Mike Seymour stand down.
Sambrook took up his current role in 2004 and prior to that had held a raft of roles including senior producer and deputy editor of the 'Nine O'Clock News' and head of newsgathering.
He joined the BBC in 1980 as a sub-editor in the radio newsroom after beginning his career on the South Wales Echo as a regional newspaper reporter.
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