Turner will be tasked with "driving the highest creative standards" and attracting new talent.
He will also grow the UK creative division and promote "experience-led innovation" for clients across Australia, China, France, Germany, Hong Kong, India, Italy and the UK.
Turner joins on 30 March, after a 16-year stint at AKQA.
He will report to Daniel Bonner, the global chief creative officer at Razorfish.
Bonner said: "It speaks volumes about the positive trajectory of our international markets that we’ve hired Nick to lead their creative output."