Nimick will be responsible for the agency's online and offline work. He takes over from Cordell Burke, who is leaving for Tequila\London after 12 years at Ogilvy.
Nimick is an Ogilvy veteran of 16 years, apart from one year spent at BBDO in Singapore. He has worked on some of the agency's most high- profile activity, including the Cancer Research UK bench, which won a D&AD pencil and the Grand Prix at the Campaign Direct awards.
He also worked on award-winning campaigns for Royal Mail, IBM and American Express. Nimick was also involved in Ogilvy Group UK's easyJet win and is writing campaigns for the account.
Nimick was promoted from creative group head to creative director in 2004. He began his advertising career at Ogilvy & Mather in 1990, working on accounts such as Ford.
Mike Dodds, the managing director of OgilvyOne London, said: "Colin has experience, multidisciplinary skills and a belief in the power of integrated communications."