- Member of Althingi for the Reykjavík North Constituency since 2007.
- Deputy Chairman of the Left-Green Movement’s parliamentary group 2007–2009.
- Member of the Economic Affairs and Trade Committee 2015–2017.
- Member of the Icelandic delegation to the Council of Europe Parliamentary Assembly 2017.
- Member of the Foreign Affairs Committee 2014–2015.
- Member of the Environment and Communications Committee 2013–2014.
- Member of the Education Committee 2007–2009.
- Member of the Economy and Taxation Committee 2007–2009.
- Member of the Icelandic Delegation to the EFTA and EEA Parliamentary Committees 2014–2016.
- Member of the EU-Iceland joint Parliamentary Committee 2014–2016 (Deputy Chairman 2014–2016).
- Member of the Icelandic delegation to the West Nordic Council 2013–2014.
- Prime Minister since 2017.
- Minister of Education, Science and Culture 2009–2013.
- Minister for Nordic Cooperation 2009–2013.