Hill will continue to be supported by the deputy head of account management, Tanya Hamilton-Smith.
He returned to JWT in 2011 from Abbott Mead Vickers BBDO, where he was an account director working on Walkers and BT. Hill previously worked at JWT on its Kellogg business.
Hill is responsible for running JWT’s Nestlé confectionery business and has extended the relationship into the digital space following pitch wins for Aero and Kit Kat.
He also oversaw the recent social campaign that saw a Kit Kat sent into space in support of Felix Baumgartner’s skydive from the edge of space.
The agency claims that the stunt delivered ten million Twitter impressions and tripled Kit Kat’s average fan growth in two days.
James Whitehead, the executive partner at JWT, said: "Ant has built a reputation for inspiring others, leading from the front with positivity and a can-do attitude. He’s always up for doing the right thing, rather than the easy thing."
Hill, who has also worked on the "man fuel for man stuff" positioning for Yorkie, spent five years at McCann London before his first spell at JWT.