The Havas-owned agency beat Aegis Group's Carat, Publicis Groupe's ZenithOptimedia and WPP Group's Mediaedge:cia in the last round of the review.
The incumbent Initiative, part of Interpublic Group, was knocked out of the pitch after the first round. Initiative had held the account since 2003.
The global account includes advertising for the First Boston brand, plus Credit Suisse's investment banking, private banking and asset management arms. It will be led out of MPG International's London office.
Credit Suisse operates in more than 50 countries but its key growth markets include China, Singapore, Hong Kong, Germany, Brazil and the UK.
The pan -European market makes up the largest share of its global media spend. UK media spend is £3 million.
The financial services company currently uses mainly print and broadcast media, but plans to increase its investment in digital media and multiplatform campaigns.
Credit Suisse also invests in partnership and sponsorship deals, and recently signed a major sponsorship deal with international news channel BBC World. The deal, which was brokered by Initiative, includes a multi-platform sponsorship of the BBC World's upcoming ‘Visionaires' series, which begins on September 1.
Credit Suisse is based in Zurich, and has main offices in London, New York and Hong Kong. It underwent a major rebrand in 2005 when it merged its main operation with the Credit Suisse First Boston investment bank and dropped the First Boston from its holding company name after 27 years.
Last year Credit Suisse ran a global advertising campaign to raise awareness of the unified brand and to reposition it as "the world's premier bank". The campaign was created by McCann Erickson, which picked up the global advertising account in 2005 from Euro RSCG.
Francesca Krist, vice president of corporate advertising at Credit Suisse, said the global appointment was effective immediately. Krist said: "We look forward to working with MPG International on our global corporate campaign."