The appointment is part of repositioning for the company, following a multimillion-dollar refurbishment of its flagship Auckland operation.
Jane Hastings, Skycity's marketing chief, said: "TBWA\Tequila best demonstrated its international creative thinking and a whole-of-business strategy in its pitch."
Skycity casinos depend largely on several hundred high-stakes gamblers, often from East Asia, who may gamble hundreds of thousands of dollars during a single visit to a casino.