Doeprofero will initially work to service existing clients of the two agencies, including Apple, Hitachi and the InterContinental Hotels Group.
Doeprofero will be headed by Stephen Cox, Yasunori Kato and Jun Niki.
It will use Profero's bespoke ad-serving software and aims to expand to provide full-service campaigns for the Japanese market.
The launch follows Profero's move into China in December 2004. The agency now has Asian offices in Hong Kong, Beijing, Shanghai and Taipei.