Klug began his design career working for Austrian electronics company Philips. He then worked for the German design company Braun, creating products for their range of consumer electronics. In particular, he worked on the famous Braun S50 electric shaver.
In 1970, Klug founded his own design company, "Klug Consulenti Design". He worked on projects for many international companies, including Italian furniture manufacturer Moroso and Italian shoe brand Geox.
Over the course of his career, Klug won numerous awards for his design work, including the Red Dot Design Award, the Best German Design Award and the IF Design Award.
Ubald Klug was considered one of the most influential designers of his time, and made a significant contribution to the rise of industrial design in Europe.