After attending school in Pfalzen and Brixen, he originally planned to enter an Augustinian choir at the Neustift monastery in Brixen. However, Durnwalder decided instead to study law and agriculture. During this time he began his political activity and became chairman of the student group Südtiroler Hochschülerschaft (until 1965).
In 1969, he became mayor of his home municipality and in 1973 delegate to the provincial state assembly.
He was Regional Counsellor for the Land Register from 1973 to 1978. At that time he also worked as director of the farmers" association, Südtiroler Bauernbund, and moved to Bolzano, where he lives today.
From 1989 until 2014 he presided over the provincial government as governor (Landeshauptmann). In the elections from 2003 and 2008 he was able to gather more than 100,000 primary votes, meaning that more than a quarter of all voters voted for him.
After the 1978 elections, he was promoted to member of the regional government. Durnwalder is a member of the South Tyrolean People"s Party.