Kajsa Ollongren served as Minister of Defence (2022–2024) and deputy Prime-Minister and Minister of the Interior and Kingdom Relations (2017-2022) of the Netherlands.

Kajsa Ollongren started her career in the civil service in 1992 at the Dutch Ministry of Economic Affairs, as an economic policy advisor. On a voluntary basis she trained young politicians from the newly established democracies of Central and Eastern Europe in the nineties. She was head of parliamentary affairs within the ministry until 2001, and director of European Integration and Strategy from 2001 to 2004, and became Deputy Director General in 2004.

In 2007 she was promoted to the Prime Minister’s Office, to become the Deputy Secretary General and in 2011 Secretary General and the most senior advisor to the Prime Minister. In that capacity she was also responsible for the coordination of the Dutch intelligence services.
After the 2014 local elections Kajsa Ollongren became the first deputy mayor in Amsterdam. Her portfolio included economic affairs, seaport, airport, art, culture, local media, monuments and tourism.

On 26 October 2017, Kajsa Ollongren was appointed as Minister of the Interior and Kingdom Relations, dealing with democracy and transparency, constitutional issues, local and regional administrations and budgets, elections, spatial planning, housing and the intelligence service. She was also Deputy Prime Minister in the third Rutte government.
From 10 January 2022 until 02 July 2024, Kajsa Ollongren was the Minister of Defence in the fourth and last Dutch government headed by Mark Rutte, and a leading voice in the support of Ukraine after the large scale Russian invasion.

Positions she took up after her tenure as a minister include the YES-Ukraine board, the MSC advisory board, associate fellow at Chatham House and non-executive board member of the Post Code Lottery.

Kajsa Ollongren studied history at the University of Amsterdam and graduated in contemporary history in 1992. She is an alumni of the Dutch institute on international affairs Clingendael and of the French school for Public administration École Nationale d’Administration (ENA), Promotion Valmy 1996-1998. She finished The Business of AI course at the London Business School in 2025. She is a reservist at the Dutch Royal Air Force, rank colonel.