Mario Annoni holds a bachelor degree in political sciences from the University of Lausanne as well as a law bachelor degree from the University of Geneva. He then obtained his lawyer licence in Berne. After chairing the regional court of La Neuveville, Courtelary and Moutier, he was elected to the Executive Council of the Berne State Council, where he headed the Department of Justice, Communes and Churches (1990–1998) and that of Public Education and Culture (1998–2006). Subsequent appointments included the Chair of the Foundation for Swiss Culture Pro Helvetia (2006-2013).
Fondazione Istituto svizzero di Roma e Milano (Chairman); Société des Forces Electriques de la Goule (Charman); Ecole de musique du Jura bernois (Chairman); Fondation Abegg (Member); Stiftung Rebhaus Wingreis (Chairman); Fondation du Musée de la Vigne du bord du Lac de Bienne (Chairman).