The promotion will not affect Wieynk’s current responsibilities at Publicis UK, where he was hired as chief executive in January by Arthur Sadoun, the chief executive of Publicis Worldwide.
As chief executive for Western Europe, Wieynk’s remit for Publicis Worldwide will include further strengthening the region’s digital capabilities, as well as managing the overall performance of the group’s constituent agencies.
Wieynk said: "There is a new level of what we can offer our clients, and the opportunity to deliver this across all of our agencies, growing stronger synergies is too great.
"I’m honoured and delighted that Arthur has asked me to guide Publicis Western Europe through its business transformation."
Wieynk’s tenure as UK chief executive has seen Dave Monk join from Grey London as the executive creative director; the relocation of Poke, the digital agency, which Publicis bought from Mother in 2013; and the acquisitions of Vivid, the shopper marketing agency, and August, the creative content agency.
Before joining Publicis UK, Wieynk was the vice-president, international, at AKQA, where he had worked for 16 years.
Sadoun said: "Bringing together these Western Europe markets under the remit of Guy will ensure greater collaboration and a broader and more streamlined offer to our clients."