John started his career with SHV, the largest family owned company in the Netherlands. He then became a partner of the law firm (Trenite) Van Doorne and was responsible for the M&A practice. For four years John acted as managing partner of this firm, one of the largest in the Netherlands at that time.

Now, John is on the Board of Bank Insinger de Beaufort and Glaxo Smith Kline in the Netherlands. John was the president of the Amsterdam Football Club AFC Ajax.