As a result of her talented approach, she soon won a number of competitions leading to successful commissions.
While she was the youngest member of the Werkbund in 1928, Kurt Schwitters introduced her to the Bauhaus architect Robert Michels in Frankfurt.
[1] For a 12-year period while the Nazi regime was in power, as a "half-Jew" Hillebrand was unable to exercise her profession.
[2] After her studios in Frankfurt and Hanover were destroyed during the war, she moved to Göttingen where she was one of the first architects to receive commissions for public buildings.
Her continuing interest can be seen in her plans for a museum for world religions for the Universal Exhibition of Architecture in Sofia in 1989.