During his years in Copenhagen he was an active member of the youth branch of the Danish Social Liberal Party, editing their paper 'Liberté'.

[2] In supporting different sides of parliament, he was sometimes referred to by the Danish media as a 'king maker', deciding which policies would pass and which would not.

[4] He was Minister for Economic Affairs in the Cabinet of Poul Schlüter III from 3 June 1988 to 18 December 1990, when his party left the government coalition after poor election results in 1990.

When the European Union's Maastricht Treaty was rejected by the Danish people in 1992, it was accepted after a referendum in 1993 adding certain opt-out concessions for Denmark.

He joined the newly created Council of the Baltic Sea States, which in 1993 successfully established the EuroFaculty in Tartu, Riga, and Vilnius, of which he became an active supporter.

[5] Niels Helveg Petersen was married to Kirsten Lee, who is also a former member of the Danish Parliament for the Social Liberal Party.