A member since 1980, Marieluise Beck is amongst the founding members of the German Green Party. In 1983, she was elected to serve as Member of the German Bundestag. After serving as a Member of Parliament of the Free Hanseatic City of Bremen from 1991 to 1994, Ms. Beck was re-elected to the German Bundestag in 1994 and has been a Member ever since.

From November 1998 to 2005, Marieluise Beck served as Federal Government Commissioner for Migration, Refugees and Integration and Parliamentary State Secretary in the Federal Ministry for Family Affairs, Senior Citizens, Women and Youth. Since November 2005, Ms. Beck has served on the Committee on Foreign Affairs of the German Bundestag in which she currently functions as spokesperson on eastern European affairs for the Green parliamentary group. She holds positions as chairperson of the German-Bosnian Parliamentary Friendship Group and is a member of the German-Ukrainian and German-South Caucasus Parliamentary Friendship Group. In addition, Marieluise Beck is a Member of the Parliamentary Assemblies of the Council of Europe and the OSCE.