Günter Steffen has founded almost 50 companies, including IT service provider tele-daten-service GmbH (TDS). In 2000, he became a member of the supervisory board of TDS. From 1998 to 2005, Günter was president of the Heilbronn–Franken Chamber of Commerce and Industry, where he was subsequently appointed honorary president in 2006. In the same year, Günter became a founding member of ZFHN.