Klaas has over 20 years of venture capital experience spanning Europe, North America and the Middle East. From 2006 until 2021, he was the Managing Partner of Entrepreneurs Fund, where his managing portfolio included companies such as inge GmbH (sold to BASF), Technolas Perfect Vision (sold to Bausch & Lomb), Prosonix Ltd (sold to Circassia), Lifeline Scientific Inc (sold to Genext), New Motion (sold to Shell) and Optinose (Nasdaq listing). In addition to General Fusion, he currently chairs AIM-listed Xeros Technology Group and serves on the Boards of SmartKem and veriNOS pharmaceuticals. Klaas is also an investment committee member for Future Fund: Breakthrough, a UK government-backed direct co-investment fund for late-stage deep tech companies.

Klaas started his career with McKinsey & Company in Amsterdam. From there, he joined Vanenburg Group where he established and managed a corporate venturing team that led investments in Europe, Israel and the US, which included WebEx. Klaas has an MSc in Applied Physics from Delft University of Technology, and an MBA from Insead.