A long-time member of Lega Lombarda and Lega Nord, Fontana was mayor of Induno Olona from 1995 to 1999. In the 2000 regional election he was first elected of LN to the Regional Council of Lombardy, of which he functioned as President until July 2006. Fontana stepped down from the post after being elected Major of Varese with 57.8% of the vote in the first round of 28 May 2006. He was re-elected in May 2011 with 53.8% of the vote in a run-off. Fontana, ineligible to run for reelection due to term limits, left the office in June 2016. Some journalists in July 2016 speculated a nomination of Fontana as LN candidate in 2018 election for President of Lombardy if the incumbent President of Region Roberto Maroni (who was elected in 2013 election for a five years term with the support of Lega Lombarda and Lega Nord - the parties of Maroni and Fontana - and with the support of the other parties members of the 2013 center right coalition) will not run for a second consecutive term.
- "Archived copy". Archived from the original on 2014-03-11. Retrieved 2014-03-11.
- After two consecutive terms, a Major (and a President of Region) is not re-eligible for a third consecutive term: for more news, see Italian electoral law of 1993 for Comuni (2004 for Region)