After earning a degree in psychology in Hamburg, Thomas began his career with Reemtsma in 1987, where he served as the product manager responsible for the “West” brand, among other duties. In 1991, he moved to Pepsi-Cola Germany, where he served as a marketing manager. In 1993, he was appointed Marketing Director for the entire beverage portfolio. Starting in 1994, he was National Sales and Franchise Director for the retail and restaurant sales of Pepsi-Cola. In 1996, he was appointed General Manager of Pepsi-Cola Germany.
In 1997, Thomas moved to Novartis, where he served as General Manager of Novartis Nutrition for Germany and Austria. In 1998, he assumed worldwide leadership of the Novartis Nutrition Division. In this position, he headed the three business units Medical Nutrition, Health Nutrition, and Consumer Retail Brands, where, among other duties, he was responsible for the leading U.S. baby food brand Gerber. In 1998, he was appointed to the Novartis Executive Committee. From 2000 to October 2007, he served as CEO of the global Novartis pharmaceuticals business. Under his leadership, the company’s revenues more than doubled from US $11 billion to the US $22.6 billion, after which he was CEO of the Novartis Consumer Health Division from 2007 to 2009.
From 2009 to 2018, Thomas served as CEO of ProSiebenSat.1 Media SE, and has been a member of the supervisory board of Bayer AG since 2012 as well as a member of the board of directors at Sivantos (Hearing Aids) since 2016 and GFK since 2017. Thomas is on the Board of Directors of Cullinan and is a member of the Advisory Board of the UBS Oncology Impact Fund by MPM Capital.