Mr Niemiec was Elected Deputy General Secretary of the European Trade Union Confederation (ETUC) at the Athens Congress in May 2011. Responsible for: employment and labour market policy; Health & Safety; the Europe 2020 strategy: Sustainable Development; Energy and Climate Change; Industrial Policy and EU enlargement. Confederal Secretary of the European Trade Union Confederation from 2003 to 2011.
Member of NSZZ Solidarność since 1980, with responsibilities at enterprise, regional and national levels. From 1992 to 2003, member of the National Commission, and its Secretary from 1998 and Vice-President from 1999 to 2002, with responsibilities related to internal affairs and European affairs.