He was born in Zuerich, Switzerland, and studied at the Kunstgewerbeschule in Zuerich with Josef Mueller-Brockmann and Hans Finsler. From 1960 to 1963 he worked in Mueller-Brockmann's studio as graphic designer, and was an assistant to Paul Rand in 1963/1964. After travels in the USA, Mexico, and work in Japan, he returned to Josef Mueller-Brockmann in 1965, and became co-owner and managing director of the advertising agency Mueller-Brockmann & Co. between 1967 and 1976. In 1977 he opened the joint Baltis and Rüegg Studios that later merged into Designalltag, in which he remained active as design consultant until shortly before his death.

Ruedi Rüegg has been teaching in universities in Zuerich and in the United States, and has held many executive functions in graphic design associations, for example as president of AGI Switzerland from 1976 to 1981. He received many awards for his posters and books. On his initiative in 1985, Carnegie Mellon University in Pittsburgh (US) established a collection of about 300 outstanding Swiss Posters from 1971 to the present.