From 2006, Þorgerður served as acting Prime Minister in the absence of Geir Haarde,[2] including during his 2009 cancer treatment.

In her final year she was elected Chairman (Ármaður) of the School Association as the second woman to serve in this position.

Þorgerður Katrín resigned as deputy chairman on 17 April 2010 after being criticised for the handling of her and her husband Kristján Arason's debts in Kaupthing Bank, which collapsed in October 2008.

Þorgerður Katrín subsequently became Minister of Fisheries and Agriculture in the short-lived government of Bjarni Benediksson.

[4][5] During the 2017 election campaign her party fell below the threshold in multiple polls and its founder Benedikt Jóhannesson therefore decided to step down as chairman in favour of Þorgerður.

The debt was never repaid, as the board of Kaupthing allowed their executives to transfer their loans and shares into private holding companies a few months before the bank was taken over by the Icelandic authorities.