Walter Momper was elected as Governing Mayor of Berlin in 1989, a post which he held during the fall of the Berlin Wall and German re- unification until 1991. In this capacity he served as President of the German upper house, the Bundesrat, from 1989 to 1990.
His political career began in 1967 when he joined the SPD. From Chairperson of the Kreuzberg Young Socialists (1969-1971) he rose to Deputy (1974) and subsequently Chairperson of the local party organisation in 1980 – a post which he held until 1985. He has been a member of the Berlin House of Representatives since 1975, was Chairperson of the Berlin parliamentary party from 1985 to 1989 and a member of the SPD national party committee from 1988 to 1993.
Walter Momper has worked in the private sector since 1992 when he joined the Dr. Ellinghaus real estate development company as Chief Executive. In 1993 he founded his own real estate company, Momper Projektentwicklungs GmbH, of which he is owner and General Manager.
From 1999 to 2001 he was vice-speaker of the Abgeordnetenhaus of Berlin (Parliament of the city of Berlin), since 2001 to 2011 he was Speaker of the Abgeordnetenhaus of Berlin.