The public-private body, which is made up of more than 17 members, including Yorkshire Post Newspapers, Leeds City Council and its Chamber of Commerce, is still being set up. But work behind the scenes has been in progress for two years.
Marketing Leeds and its campaign will launch in mid-May when its logo is finalised. The scheme will promote the city as a tourist and business destination.
The push will promote the shopping, cafe culture, nightlife, parks and nearby countryside, as well as the growing business district.
The campaign is expected to target the print media in France, Germany, Italy and Spain, as well as a number of North American cities.
Known traditionally for its textile industry, companies such as First Direct have moved to Leeds in recent years and the city is a now a hub for call centres.
Poulter senior account director Adrian Johnson said: 'In the past ten years Leeds has become the biggest financial sector outside London. In addition, its legal centre is the third biggest in the UK. Leeds' media sector is also one of the fastest-growing in the UK.'
Public investment in the city has helped lever significant private investment.
For example, the Millennium Square development has attracted £15m of investment from private developers.
There is also £3bn worth of large-scale developments for Leeds in the pipeline, said Marketing Leeds.
Poulter beat five other shortlisted agencies to win the account. It replaces Leeds-based Brahm PR, which was employed directly by Leeds City Council.