Certainly influenced by his studies in architecture and his time at the Bauhaus in Weimar, Grossberg devoted himself to design projects in the late 1920s. In 1927, he collaborated with the architect Erich Mendelsohn in Berlin on designing a stained glass window for the chapel at the Jewish cemetery in Königsberg. In 1928, the two worked together again on the interior design of the 'Universum' picture house in Berlin.
Between 1929 and 1932, Grossberg took on several commissions from private individuals for apartment renovations and interior design in southern Germany. These mostly involved modernising old buildings from the Wilhelminian era. He also furnished a small hat shop in Nuremberg.
Grossberg chose the interior design for the various apartments with great care: modern lighting and furniture, often in line with Bauhaus design, such as tubular steel furniture, as well as floor coverings and wall colours. Grossberg's preserved documents relating to these commissions include black-and-white photographs, some of which contain precise colour and material descriptions.
