Jacob Kohnstamm was appointed in 2004 as Chairman of the Dutch Data Protection Authority (College bescherming persoonsgegevens) for a six-year term by Royal Decree. He has been appointed for a new six-year term as from August 2010.
Since February 2010 he also is Chairman of the Article 29 Working Party. All supervisory authorities in the European Union and the European Economic Area take part in this Working Party that plays an important role in the establishment of European policy.
Jacob Kohnstamm had been a member of the Senate of the States General for D66 (Liberal Democrats) since 1999. In addition, he was chairman of a large number of organisations and committees including the Regieraad ICT Politie [Board for Information and Communications Technology for the Police].
He was State Secretary for Internal Affairs between 1994 and 1998 and in particular was responsible for developing the Large Cities Policy.
After completing his studies in law at the University of Amsterdam, J. Kohnstamm worked as a lawyer between 1977 and 1981 and between 1982 and 1986.
In 1981 he was elected a member of the House of Representatives of the States General. He was a spokesman for his political party in the areas of defence, the police and justice. From 1982 to 1986 he held the position of party chairman of the Liberal Democrats.
Between 1986 and 1994 Kohnstamm was again a member of the House of Representatives. In the first session period he was spokesman for internal affairs, the police and the Middle East. In this period he was also Chairman of the standing parliamentary committee National Ombudsman. In the parliamentary period that followed, namely between 1989 and 1994, he was spokesman in the policy areas of public health, the police and the Middle East and also chairman of the standing parliamentary committee for the police.
- since 2011 Chairman of the Executive Committee of the International Conference for Data Protection and Privacy Commissioners
- since 2011 Member of the Supervisory Council of Stichting Vluchteling [Netherlands Refugee Foundation]
- since 2010 Chairman of the Mediafonds [Dutch Cultural Media Fund]
- since 2010 Chairman of the Board of the Internationaal Kamermuziekfestival Schiermonnikoog [International Chamber Music Festival Schiermonnikoog]
- since 2008 Chairman of the Board of Stichting Ipermestra [Ipermestra Foundation for Music Projects]
- since 2008 Member of the Initiatief- en Referendumcommissie Gemeente Amsterdam [Initiative- and Referendum committee of the municipality Amsterdam]