Following her studies, Mrs. Hennis started working for the Directorate-General for Enlargement of the European Commission in Brussels. During that time, she spent two years working for the EC in Riga, Latvia.

From 2000 to 2002, she worked as a consultant for KPMG in Amstelveen, Netherlands, after which she became a political assistant to the Municipal Executive of Amsterdam, a position she held until 2004.

From 2004 to 2010, Mrs Hennis was a Member of the European Parliament for the VVD (People’s Party for Freedom and Democracy). As a MEP, she was a member of the Committee on Transport and Tourism and the Committee on Civil Liberties, Justice and Home Affairs.

On 17 June 2010, Mrs Hennis became a Member of the Dutch House of Representatives for the VVD, focusing on security, police, equal treatment and disaster and crisis response.

On 5 November 2012, Mrs J.A. Hennis-Plasschaert was appointed Minister of Defence in the Rutte-Asscher government.