Klinz was a Partner with McKinsey & Company in the United Kingdom, Germany and France. Subsequently, he served as a Member of the Executive Board of a Swiss Corporation. After German reunification he joined for the Executive Board of Treuhandanstalt, the German Government's agency for privatisation of the former East German industry. He finished his business career as CEO of a large German corporation in 2003 when he decided to go into European politics.
From 2000 to 2004, Klinz held the (honorary) position of President of the Chamber of Commerce and Industry (IHK) Frankfurt am Main. From 2003 to 2004 he was the Vice-President of Eurochambres in Brussels.
In 2009 Klinz replaced Peter Skinner as Chair of the steering committee of the European Parliamentary Financial Services Forum, a platform "promoting effective dialogue between the financial industry and MEPs and contributing to a greater understanding of financial services issues".[3]
In 2015, the European Commission asked Klinz to chair the board of the European Financial Reporting Advisory Group (EFRAG), which was set up in 2001 as a private association to advise the Commission on accounting standards and other aspects of financial reporting.[4] Klinz did not take up this position in May 2015 due to ill health; Jean-Paul Gauzes was appointed instead.[5]