He joins from his role as the chief executive of the Chinese digital media company In-Game Media, and takes over from Gavin Heron, who is relocating to head TBWA's Johannesburg office.
Before joining In-Game Media, Chan spent 12 years working at Leo Burnett in Hong Kong and Shanghai, where he became the managing director.
Keith Smith, the president international of TBWA\Worldwide, said: "Donald joins with an impressive set of credentials and a proven track record in China. He was the ideal candidate for the role."