In his new role as the executive creative director and chief creative officer, Moore will be responsible for more than 100 people. He will join the agency in September.
Moore replaces Joel Sobelson, who left Wunderman New York last year.
Peter White, the senior creative, has been overseeing the department in the interim. Moore will report to the agency's president, Steve Zammachi.
Moore was the executive creative director of Tequila\ London for 14 months following its merger with TBWA\ GGT, where he had been the creative director for five years. He left earlier this year after it emerged he had been involved in conversations with Mother about plans to launch a direct arm.
Moore joined TBWA\GGT from BHWG (now Proximity London) where he was the creative director. Before that, he worked at Woollams Moira Gaskin O'Malley.
He began his career as a copywriter at Wunderman.
Moore said: "It's a new kind of opportunity for me. I'm looking forward to working with some interesting people on some great clients."
Zammachi added: "Nick's knowledge of every aspect of relationship marketing, his creative insight and engaging personality are the perfect combination for our increasingly diverse multichannel business."