[2] Between 1923 and 1926, he was employed in the United States at the offices of Frank Lloyd Wright (Spring Green and Los Angeles), Schmidt, Garden & Martin (Chicago), and Drake Brothers (Evanston).

[2][3] Upon his return to Switzerland, Moser collaborated with other Swiss architects to design the model furnishings for Ludwig Mies van der Rohe's apartment building at the Werkbund exhibition in Stuttgart in 1927.

[2] In 1928, Werner co-founded the Congrès Internationaux d'Architecture Moderne (CIAM) in La Sarraz, Switzerland, along with 28 prominent European architects, including Le Corbusier, Sigfried Giedion, Hendrik Berlage, and his father.

[2][3] In 1931, Moser – along with architects Sigfried Giedon and Rudolf Graber – founded the Wohnbedarf, a modern interior design showroom in Zurich to which he contributed numerous models.

[5] In later projects, Moser and HMS gravitated towards the construction of office spaces, an example of which is the 14-story high-rise Zur Palme, built in collaboration with architect André M. Studer (1959–1964).