Williams, a creative director on Publicis Dialog's much-vaunted "hype" campaign for HP, will be London-based and will work closely with Harrison Troughton Wunderman's creative partner, Steve Harrison.
However, he will report to Simon Milliship, the executive creative director of Wunderman's interactive arm in the UK.
Milliship said: "It's terrific news for Wunderman and, more significantly, for our client partners. We are immensely proud of our work and Jon's arrival, with his flair for motivation, creative impact and effectiveness, will enhance it further in the interests of our clients."
Before his four-year stint at Publicis' digital outfit, Williams spent eight years at PTK, now Grey PTK, where he was responsible for setting up the agency's new interactive division.
His career has also extended through the line to include spells at J Walter Thompson, WCRS and Saatchi & Saatchi.
He has picked up Cannes Lions, a D&AD silver award and the Marketing Association Grand Prix.
Williams said: "This is undoubtedly the best job in London. It is so refreshing to find a collection of driven, talented people who genuinely 'get it'. The opportunities to deliver channel-spanning contagious ideas are amazing."
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