The agency's founding client is Fonterra, a global account won by the network last August, and the agency is in talks with a number of other undisclosed advertisers.
BBDO Vietnam was set to launch in a non-equity partnership with local shop Golden Advertising, but exploratory talks broke down. It is believed the two parties disagreed over which would have greater control over the new company.
BBDO's below-the-line arm Proximity will later be added to the agency offering. BBDO Asia-Pacific CEO Chris Thomas said: "Our first focus is BBDO, and Proximity will come in due course. That said, the agency will be integrated from the outset with the full suite of creative capabilities - which you absolutely have to have to operate in this market."
He added: "It is very much a start-up, and we have no pre-conceived notion of the size we're looking to achieve. We will focus on working with clients who demand high-quality advertising - that's the way the agency will grow."
Smail, who has two months of his contract to see out at JWT, will formally open the agency in April. He has operated in the country since 1997. Before JWT, he had spells at Y&R and Ogilvy & Mather. Smail was the first Vietnam-based creative to win a Cannes Lion, and has also won at One Show.
"I've been in discussions with David for some months. He's doing good work, winning awards and is a talent magnet for local people," said Thomas.
Smail added: "I'd like this (set up) to be considered the first real agency started in Vietnam based on the strength of its creative."