From 1987 to 1996 Citterio together with Terry Dwan designed offices in Europe and Japan.
In 1999 Antonio Citterio and Patricia Viel founded "Antonio Citterio and Partners" as a multidisciplinary design studio for architecture, industrial design and graphics. The studio develops projects for residential and commercial complexes, industrial facilities, preservation/restoration of public buildings, planning of workspaces, offices, showrooms, and hotels; it is also active in the area of corporate communications and carries out coordinated image projects, installations/outfitting and graphics.
Antonio Citterio currently works in the industrial design sector with Italian and foreign firms such as Ansorg, Arclinea, Axor-Hansgrohe, Aubrilam, B&B Italia, Flexform, Flos, Fusital, Guzzini, Iittala, Inda, Kartell, Maxalto, Sanitec Group - Pozzi Ginori, Simon Urmet, Technogym, Tre Più, and Vitra.
In April of 2000, the company opened new headquarters in Milan at Via Cerva 4, and a month later, offices in Hamburg, at Wrangelstrasse 75b.
In 2004 a monograph entitled "Antonio Citterio Industrial design" was published by Electa, and in 2005 another monograph entitled "Antonio Citterio", edited by Luigi Prestinenza Puglisi, was published by Edilstampa.
Since 2006, Citterio has been a professor of design at the Architecture Academy of the University of Italian Switzerland (Accademia di Architettura dell’Università della Svizzera Italiana).
In 2007 the jury for the Mies van der Rohe Award selected Citterio’s "GlaxoSmithKline Day Nursery" project for inclusion in its travelling exhibition and catalog.