In 1983 at age 23, he became a municipal councillor in Chambéry under Gaullist mayor Pierre Dumas. In 1985, he was elected to the General Council of Savoie for the Rally for the Republic, becoming the youngest councillor. He was Vice President of the General Council under the presidencies of Michel Barnier (1994–98). When seeking a third cantonal term in 1998, he was defeated by Socialist candidate Thierry Repentin. However, he was re-elected as municipal councillor on the RPR or UMP lists in 1989, 1995, 2001 and 2008.
In the 2009 European elections, he was the sixth candidate on the Union for a Popular Movement list in the South-East region, but he was not elected. However, the fifth UMP MEP, Nora Berra, will not sit in the European Parliament due to her appointment to the government and Dantin will take her seat.
- Biography on European Parliament