She served in the position of deputy representative to the Norwegian Parliament from Telemark during the term 1989–1993 and from Oslo during the term 1997–2001. During the latter term, from April 2000, she moved up as a regular representative meanwhile Erik Solheim was appointed as a peace negotiator in Sri Lanka. When the Socialist Left Party entered the Cabinet in 2005, Rugtvedt was appointed State Secretary in the Ministry of Education and Research.
On the local level, she served as a member of Skien city council from 1987 to 1989.
In addition, she was the leader of Socialist Youth from 1990 to 1992.