On the local level Widvey was a member of Karmøy municipal council from 1979 to 1989, the last six years in the executive committee.

She was elected to the Norwegian Parliament from Rogaland in 1989, and was re-elected on one occasion.

From 2002 to 2003, during the second cabinet Bondevik, Widvey was appointed State Secretary of the Ministry of Fisheries.

In 2004, she was appointed Norwegian Minister of Petroleum and Energy, an office she left, along with the rest of the second cabinet Bondevik, after their 2005 election defeat.

A physical therapist by education, she was deputy leader of the Norwegian Sporting Association of People with Disabilities 1985–1987.