Zeugin studied in Lucerne at the Schule für Gestaltung and as a trainee in a graphic studio (1948–52). He started his practice in Basel and became an art director in a Lucerne advertising firm (1954–57). From 1958 he worked independently from his own studio and in 1965 turned it into a design and advertising agency, operating with a number of employees. He was the president of the Bund Graphischer Gestalter der Schweiz (1963– 1972) and of the Arbeitsgemeinschaft Schweizer Graphiker (1972–75). Mark taught graphic design at the Kantonale Schule für Gestaltung in Biel. He created many awardwinning posters, for CSIO in Lucerne, Caritas Schweiz and the Lucerne region (‘Vaterland’ with a big red V) among other clients. He also designed very effective logotypes. His painting took up a lot of his leisure time. He also had many exhibitions of his work.