As a functionary of the SED, the ruling political party of East Germany, Collein was an important figure in forming and implementing the government's new socialist building policies in the 1950s and 1960s.

He undertook the preliminary course run by László Moholy-Nagy, studied in the carpentry workshop under Marcel Breuer and Josef Albers, and took classes by Paul Klee, Wassily Kandinsky and Joost Schmidt.

[2] As a student he worked on the ADGB Trade Union School project in Bernau bei Berlin, which is now part of the Bauhaus World Heritage Site.

[8] The purpose of the visit, from 12 April to 25 May 1950, was to study Soviet town planning methods in order to develop strategies for rebuilding post-war East Germany.

[4] The tour resulted in a document called The Sixteen Principles of Urban Design (German: Die Sechzehn Grundsätze des Städtebaus), which was written on 28 April 1950 in the Soviet Union.

It was strongly influenced by Soviet planners, who had criticised East Germany's previous general reconstruction plan.

[2][9] The academy was a government agency that operated as the central research institution for architecture and construction in East Germany.

Together with Josef Kaiser and Werner Dutschke, Collein was involved in the second phase of construction of Karl-Marx-Allee (1959–1965), on the section between Strausberger Platz and Alexanderplatz.