[6][7][8] Beliën worked as a journalist for Gazet van Antwerpen from 1982,[2] until he was fired in 1990 for leaking a story about King Baudouin's opposition to legalised abortion in The Wall Street Journal.

[1][7][8] He co-founded the Brussels-based Centre for the New Europe in 1993, a neoliberal euroskeptic think tank with attention to social conservative issues affiliated with the Bruges Group, together with lawyer Fernand Keuleneer, after having founded the magazine Nucleus together in 1990.

The article caused a media storm, and led him to receive a letter from the Centre for Equal Opportunities and Opposition to Racism for "incitement to violence", ordering him to remove the post from the site or face prosecution.

[10] In 2007, Beliën used his contacts with the Vlaams Belang party to take part in hosting the international counter-jihad conference in Brussels, which brought together at least seventy organisations and individuals for two days of speeches and networking opportunities.

[2] Beliën has later been described as a key ideologue of the Dutch Party for Freedom (PVV), having served as a ghostwriter, speech writer, foreign secretary, fundraiser and personal assistant for Geert Wilders since 2010.