In November 2009 Hahn was nominated by the Austrian Federal Government to succeed Benita Ferrero-Waldner as member of the European Commission from Austria.
Reportedly, while the ÖVP's first choice for Commissioner would have been Wilhelm Molterer, this was vetoed by chancellor Werner Faymann, opening the road for Hahn.
Faymann later confirmed him in 2014
President Barroso appointed Hahn as European Commissioner for Regional Policy.
Hahn's appointment to the European Commission meant that he had to resign his position as chairman of the Austrian People's Party in Vienna, as commissioners of Barroso Commission II are not allowed to hold political office nationally, although party membership is permitted.

He was twice appointed Acting Commissioner for Justice, Fundamental Rights and Citizenship in Viviane Reding's stead, from 19 April 2014 – 25 May 2014 while she was on electoral campaign leave for the 2014 elections to the European Parliament and from 1 July 2014 – 16 July 2014 after she took up her seat.

During his term as European Commissioner for Regional Policy (February 2010 – November 2014) Hahn implemented an ambitious and comprehensive reform of EU Regional Policy, linking it closer with EU economic governance and macro-economic conditions; introducing clearly defined conditions; and establishing a better evaluation system.
Based on the new regulation, European regions have developed so called smart specialisation strategies to identify their particular strengths and potentials as the basis for investments.
The adoption of smart specialisation strategy was an ex-ante conditionality for the approval of regional programs for the period 2014–2020.

Despite cuts in the overall EU budget, Hahn succeeded to keep the high level of financial support for strategic investments in the new period (2014–2020): Funding for regional and cohesion policy in 2014–2020 amounts to 351,8 billion Euro.
Taking into account the national contribution of member states, and the leverage effect of financial instruments, the overall impact of investments is likely to be about 600 billion Euro.

Parts of the reform were already implemented in the last year of the Barroso term.
Thanks to increased flexibility, allowing reprogramming of structural funds, the reformed Cohesion Policy paid also an important role in overcoming coping with the economic crisis.
Measures in this context were e.g. reallocation of unused funds for education, training and employment as well as for providing urgently needed liquidity for enterprises .

The reform, endorsed by the Council and European Parliament with overwhelming majority and strongly supported also by stakeholders and the Committee of the Regions, established Hahn's reputation as a "forward looking, bold reformer".

Despite cuts in the overall EU budget, Hahn succeeded to keep the high level of financial support for strategic investments in the new period (2014–2020): Funding for regional and cohesion policy in 2014–2020 amounts to 351,8 bn EUR.
The reform, endorsed by the Council of the European Union and the European Parliament with overwhelming majority and strongly supported also by stakeholders and the Committee of the Regions, established Hahn's reputation as a "forward looking, bold reformer".
More detailed information on the fundamental reform of Regional Policy can be found here: Cohesion Policy Reform in 10 points The Reform of Cohesion Policy
In November 2009 Hahn was nominated by the Austrian Federal Government to succeed Benita Ferrero-Waldner as member of the European Commission from Austria. Reportedly, while the ÖVP's first choice for Commissioner would have been Wilhelm Molterer, this was vetoed by chancellor Werner Faymann, opening the road for Hahn. Faymann later confirmed him in 2014
President Barroso appointed Hahn as European Commissioner for Regional Policy. Hahn's appointment to the European Commission meant that he had to resign his position as chairman of the Austrian People's Party in Vienna, as commissioners of Barroso Commission II are not allowed to hold political office nationally, although party membership is permitted.
He was twice appointed Acting Commissioner for Justice, Fundamental Rights and Citizenship in Viviane Reding's stead, from 19 April 2014 – 25 May 2014 while she was on electoral campaign leave for the 2014 elections to the European Parliament and from 1 July 2014 – 16 July 2014 after she took up her seat.
During his term as European Commissioner for Regional Policy (February 2010 – November 2014) Hahn implemented an ambitious and comprehensive reform of EU Regional Policy, linking it closer with EU economic governance and macro-economic conditions; introducing clearly defined conditions; and establishing a better evaluation system. Based on the new regulation, European regions have developed so called smart specialisation strategies to identify their particular strengths and potentials as the basis for investments. The adoption of smart specialisation strategy was an ex-ante conditionality for the approval of regional programs for the period 2014–2020.
Despite cuts in the overall EU budget, Hahn succeeded to keep the high level of financial support for strategic investments in the new period (2014–2020): Funding for regional and cohesion policy in 2014–2020 amounts to 351,8 billion Euro. Taking into account the national contribution of member states, and the leverage effect of financial instruments, the overall impact of investments is likely to be about 600 billion Euro.
Parts of the reform were already implemented in the last year of the Barroso term. Thanks to increased flexibility, allowing reprogramming of structural funds, the reformed Cohesion Policy paid also an important role in overcoming coping with the economic crisis. Measures in this context were e.g. reallocation of unused funds for education, training and employment as well as for providing urgently needed liquidity for enterprises .
The reform, endorsed by the Council and European Parliament with overwhelming majority and strongly supported also by stakeholders and the Committee of the Regions, established Hahn's reputation as a "forward looking, bold reformer".
Despite cuts in the overall EU budget, Hahn succeeded to keep the high level of financial support for strategic investments in the new period (2014–2020): Funding for regional and cohesion policy in 2014–2020 amounts to 351,8 bn EUR. The reform, endorsed by the Council of the European Union and the European Parliament with overwhelming majority and strongly supported also by stakeholders and the Committee of the Regions, established Hahn's reputation as a "forward looking, bold reformer". More detailed information on the fundamental reform of Regional Policy can be found here: Cohesion Policy Reform in 10 points The Reform of Cohesion Policy
Johannes Hahn