Stefan Schmertzing began more than 20 years ago in the communications industry, in today's FCB. He then spent 3 years in Germany, at J. Walter Thompson, and in 1994 founded the first of his own agencies, Tell Advertising Agency, which he merged in 1998 with TBWA where he was active as Managing Partner.

In 2005 he founded schmertzing&co, which was Agency of the Year. In 2007 schmertzing&co integrated with CCP, Heye. In 2009 Schmertzing founded the agency Wunderknaban for social media and online marketing with his partner Stefan Unterberg (former Online - Managing Director of Vorarlberger medienhaus). Wunderknaben has clients such as Ronald McDonald House, Rewe Austria (clever, Ja!Natürlich) IKEA in partnership with GroupM, bwin and 3M.