From 1949, Neumann was a representative in the Volkskammer, from 1954 a member of the Central Committee and candidate, and from February 1958 a member of the SED Central Committee's Politburo. From 1957 to 1961, he was SED Central Committee Secretary, from 1961 to 1965 chairman of the People's Economic Council ("Volkswirtschaftsrat"), and from 1965 to 1968 Minister of Materials Management. From 1962, he was a member of the Presidium of the Council of Ministers, and in 1968 he was one of the first two acting chairmen of the Council of Ministers.