Bachelor of Science in Public Administration, University Uppsula, 1990. Postgraduate, University Uppsula, 1994. Licentiate degree in Economics, University Uppsula, 1994.
In 2015 he was named Executive Director for Northern Europe at the International Monetary Fund. Östros has a licentiate degree (a graduate degree in the Swedish university system) in economics from Uppsala University. He also served as a councillor in the Uppsala Municipal Council.
In 1996, he became the Minister for Taxation at the age of 31, under the Cabinet of Göran Persson, and later served as Minister for Education from 1998 to 2004. In 2004 he switched posts with Leif Pagrotsky and became Minister for Enterprise and Energy, a position he held on to until the Social Democratic defeat at the general elections of 2006. Östros was also the deputy chairman of the Riksdag's committee for Industry and Trade from 2006 to 2008.
Östros left the party executive committee at about the same time, and subsequently left the Riksdag in July 2012, having spent a total of 17 years as an MP. It has often been said that former Prime Minister Göran Persson has a lot of confidence in Thomas Östros, and he was mentioned in speculations about possible successors to Persson. Östros was appointed CEO of the trade association Swedish Bankers' Association in 2012, a position he resigned from in 2015, only to later be named Executive Director for Northern Europe at the IMF.
In 2008 he was appointed economic policy spokesperson for his party, following a leadership dispute between his predecessor Pär Nuder and the newly appointed party chairman Mona Sahlin. A post he was forced to resign from in March 2011, coinciding with the ascension of Håkan Juholt as chairman, a candidate he refused to endorse or publicly support.
During his time at university, he was an active member of the local branch of Social Democratic Students of Sweden. In 1994 he was elected to the Riksdag as a Member of Parliament.