She worked as a lawyer from 1987 to 1998. She was elected to the district court of Trin in 1985, presiding from 1991 to 1997. As a member of the Swiss People's Party, she was the cantonal legislative of Grisons 1994 to 1998, and in 1998 was elected to the cantonal government as the first woman, acting as president in 2001 and 2005. Widmer-Schlumpf was named as an alternative candidate to Christoph Blocher by the Christian Democrat, Social Democrat and Green fractions in the Swiss Federal Council elections of 12 December 2007. In the first round, she received 116 votes, compared to 111 votes for Blocher. In the second round, she was elected federal councillor with 125 votes, 115 votes going to Blocher and 6 spurious, empty or invalid. She accepted her election on 13 December 2007. She assumed Blocher's old portfolio as head of the Department of Justice and Police. After her election, Widmer-Schlumpf was intensely opposed by the national leadership of the Swiss People's Party, who denounced her as a traitor to her party for accepting an election that she won without the support of the party. Immediately after her election, she was excluded from the party's group's meetings, as was her colleague Samuel Schmid. Widmer-Schlumpf was elected Vice President of the Confederation for 2011, alongside President Micheline Calmy-Rey. On 14 December 2011 she was elected President of the Confederation for 2012.