For a long time, Modrow headed the Socialist Unity Party of Germany which governed the former German Democratic Republic (GDR). He became the country’s prime minister in November 1989 after the fall of the Berlin Wall.
As the last communist leader, he was involved in the democratic reforms which paved the way for German reunification. In April 1990 he was able to resign after his party lost the first free elections in the country. He remained critical of German unification. According to him, West Germany should have made more concessions. Modrow was then still active in the Bundestag and in the European Parliament.