Charles Gielen concentrates on patent and trademark litigation. He is a part-time professor in IP law at Groningen University and has authored various IP handbooks. Charles is a member of the Executive Committee of the International Association for the Protection of Industrial Property (AIPPI) and acts as Chairman of the Special Committee on Biotechnology. He is the past President of the Dutch group of AIPPI; recently he has been appointed Member of honour of this association. Furthermore he is a member of the standing advisory committee to the Dutch Government on trademark and design law.

In 2006, Professor Charles Gielen received the INTA President Award, one of the highest honours given to intellectual property practitioners.

Interviewees ranked Charles in Chambers Global Guide 2006 as the most important trade mark player in the Dutch field and Chambers described him as the team's undoubted rainmaker. In the Chambers Global Guide 2008 and the Chambers Europe Guide 2008 Charles is revered as still the icon of trade mark law in the Netherlands. He leads the practice and earns considerable kudos from his contemporaries and clients, who describe him as a lawyer of considerable talent. Although he has made his name in trade mark law, he also handles patent litigation and sits on the panels of many national and international IP committees. Academically exceptional, he is admired across the market for his active practice and meticulous technical abilities.

Charles graduated from Tilburg University in 1971 and obtained his doctorate degree at Utrecht University in 1991.