After qualifying as an industrial engineer in Rosenheim, Klaus-Peter Siemssen first worked for Siemens in Europe and the USA. Between 1997 and 2010 he played a key role in the brand development of Siteco Beleuchtungstechnik GmbH (founded by Siemens). He held a number of positions. From 2006 he was distribution and marketing manager in the new company. Since April 2010 he has been the CEO of Berlin-based Selux Aktiengesellschaft. Klaus-Peter Siemssen has also been a guest lecturer in brand development at Rosenheim University of Applied Sciences.