His appointment follows Vodafone's decision to move its global advertising business into the JWT network in May. This move saw WCRS lose its slice of Vodafone's £45 million UK budget.
Although Wieden & Kennedy remains the global creative agency, JWT will provide strategy and advertising materials for Vodafone's global brand campaigns.
Turner-Smith joins from Young & Rubicam New York where he has worked for two-and-a-half years as the senior partner and global account managing director on the network's Citibank business.
Since 2001, Turner-Smith worked on the consumer and corporate Citibank business through Asia, Latin America, Europe, the Middle-East and Africa.
He was responsible for adopting and developing a single brand positioning for Citibank outside of the UK.
"This is one of the great opportunities that come along in your career. Vodafone is the largest mobile phone operator in the world, and I see it as an exciting challenge working with it to further develop its brand positioning, Turner-Smith said.
Michael Maedel, the president and chief executive of JWT Europe, the Middle-East and Africa, said: "Derek is perfectly cast to work on the Vodafone business and lead the JWT team which will be reporting to him."
Turner-Smith, who was made a board director at Y&R in 1994, has previously worked as the global account managing director on the Pirelli Tyres business.