From 1990 to 1996, he worked as an adviser at the Polish Ministry of Finance, and subsequently at the Polish Ministry of Ownership Transformations and at the Central Planning Office. He became a consultant to the World Bank in 1996.
From 1994 to 1996, Professor Belka was Vice-Chairman of the Council of Socio-Economic Strategy at the Council of Ministers, and then, economic adviser to the President of the Republic of Poland.
Professor Belka served twice as Deputy Prime Minister, Minister of Finance: in the government of Włodzimierz Cimoszewicz in 1997 and in the government of Leszek Miller from 2001 to 2002.
From May 2004 to October 2005, Professor Belka served as Prime Minister of Poland. On 10 June 2010, Professor Belka was approved by the Parliament of the Republic of Poland as President of Narodowy Bank Polski and Chairman of the Monetary Policy Council.
Professor Belka has also held numerous high-ranking positions within the international community. In 2003, he served as Chairman of the Council for International Coordination for Iraq and as Director of Economic Policy in the Coalition Provisional Authority (2003-2004), where he was responsible for the currency reform, the development of a new banking system and the supervision of the Iraqi economy. From 2006 to 2008, he held office in the United Nations as Executive Secretary of Economic Commission for Europe (UNECE) in Geneva. In November 2008, he assumed office as Director of the European Department at the International Monetary Fund.
From November 2011 to October 2015, Governor Belka chaired the World Bank/IMF Development Committee. In January 2011, he was elected a Member of the Steering Committee of the European Systemic Risk Board. Since June 2012, he has chaired the Vienna 2.0 Initiative Steering Committee.
Professor Belka has published over 100 scientific papers devoted primarily to the theory of money and anti-inflation policy in developing countries.