Hundstorfer was from December 2008 to January 2016 the Federal Minister for Labour, Social Affairs and Consumer Protection.

After Hundstorfer had been elected President of the ÖGB, he resigned from the Vienna legislature and municipal council on 25 January 2007.

On 27 March 2006 he took over ad interim the ÖGB presidency after the resignation of Fritz Verzetnitsch during the BAWAG affair.

He remained president ad interim until the election of his successor Erich Foglar from OGB Board, when Hundstorfer had already been designated to Minister of Social Affairs and Consumer Protection in the First Faymann government.

He was the honorary president of the Anton Proksch Institute and of the Vienna Handball Federation.