The artist is recognised for his work within the German Expressionist and New Objectivity movements. His approach relied on a rapid, economical line that captured a subject without unnecessary detail. Grossmann produced numerous lithographs and etchings depicting the cultural elite of the Weimar Republic. These portraits possess a journalistic quality, recording the faces of writers and actors with immediacy. His sketches of Berlin street life provide a direct record of the city during a period of social change.

Modern collectors value Grossmann for his ability to suggest complex scenes through minimal marks. His prints offer a window into the intellectual circles of early twentieth-century Europe. The monochromatic nature of his etchings makes them suitable for contemporary interiors that prioritise clean lines. His work demonstrates the use of precise strokes to define a personality or a place.