Karl is the founder of the Zurich Film Festival. He sold the festival to NZZ Medien AG in 2016. He served as the Artistic Director of ZFF for 15 years until 2019 and was the driving force behind its success and growth. He is also the founder of the Zurich Summit and the production company Zurich Avenue AG. Karl is married to Viviana Vezzani, and they have a daughter. They live in Zurich and Los Angeles.
