By the age of 27 Armin Hofmann had already completed an apprenticeship in lithography and had begun teaching typography at the Basel School of Design. His colleagues and students were integral in adding to work and theories that surrounded the Swiss International Style, which stressed a belief in an absolute and universal style of graphic design. The style of design they created had a goal of communication above all else, practiced new techniques of photo-typesetting, photo-montage and experimental composition and heavily favored sans-serif typography.
He taught for several years at the Basel School of Design and he was not there long before he replaced Emil Ruder as the head of the school. The Swiss International Style, and Hofmann, thought that one of the most efficient forms of communications was the poster and Hofmann spent much of his career designing posters, in particularly for the Basel Stadt Theater. Just as Emil Ruder and Joseph Müller-Brockmann did, Hofmann wrote a book outlining his philosophies and practices. His Graphic Design Manual was, and still is, a reference book for all graphic designers.