According to RTL, he now has the rank of “conseiller de gouvernement 1re classe” (senior-level government advisor) under prime minister Xavier Bettel. Siweck had been an advisor from 2005 to 2013 under in the government led by Jean-Claude Juncker.

Siweck was editor-in-chief at the Wort for 4 years; he left its publisher, Saint-Paul, in September. The decision was taken after there had been discussions about the editorial line when Luc Frieden, a former finance minister, became chairman of the board.