Þór has been active as a union trustee for the Reykjavik Seafarers Union, Anti-Death Penalty Coordinator for Amnesty International (South-East Region U.S.A.), organizer for South-Carolinians Against the Persian Gulf War, activist for Icelanders Against the Iraq War and is one of the founders of the Citizens' Movement (later The Movement). Þór is also a member of Amnesty International, The Movement, Future Iceland, The Iceland Nature Conservancy, The Reykjavik Academy, Unity-Grassroots Association, The Reykjavik Angling Club, Wave-Democracy Club, and the Union for Democracy and Public Interest. Þór is divorced after a ten-year marriage and has one daughter, Hildigunnur, born in 1999.