A member of FDP.The Liberals, Cassis was elected to the Federal Council on 20 September 2017 following the resignation of Didier Burkhalter.

He was a cantonal doctor in Ticino from 1996 to 2008 and vice president of the Foederatio Medicorum Helveticorum (FMH, literally "Swiss Medical Association") from 2008 to 2012.

[5] Residing in the canton of Ticino, Cassis served in the National Council from 4 June 2007 to 30 October 2017 where he was affiliated with FDP.The Liberals.

[12][13] Cassis took office on 1 November 2017 as head of the Department of Foreign Affairs, succeeding Didier Burkhalter.

[14][15][16] He caused some controversy shortly after his election when the media reported that he addressed and joined ProTell, a gun rights advocacy group, nine days before his election, something that might have made his relationship with the EU difficult as Foreign Minister due to discussions over joint gun policy.

[17] A member of the Swiss Parliament's Israel Friendship Group, Ignazio Cassis defends positions perceived as pro-Israeli.