Between 1950 and 1959 Hermann studied medicine at the University of Utrecht. In 1959 she took her doctor's exam and started to work as a neonatal and pediatric doctor and as a health care teacher. Between 1973 and 1978 she works a research for the Central Institute for the Development of Tests. In 1978 she returned to the medical work as chief researcher of social medicine at the Radboud University Nijmegen. In 1982 she became directed of the municipal health service of Heemskerk. In 1984 she was promoted in medicine on basis of dissertation on women doctors in the Netherlansd. In 1985 she joined the board o fthe Dutch Society for Medicine in addition to her work as director. In 1991 she became member of the Social Insurance Bank. Afterwards she became a member of the Association for Dutch Women Doctors. In 1992 she took her early retirment. She became officer in the order of Orange-Nassau. In 1996 she founded the Paul Hermann fund, named after her father, which supports young cellists. Her father was a cello player and composer of Hungarian background. He was murder in Auschwitz-Birkenau.
In the 1998 election Hermann became member of the Tweede Kamer for the GreenLeft. She was spokesperson on health, welfare and food safety. In 2001 she proposed an amendment on the Law on Tobacco, which should ensure a smoke free working place for all. This amendment led to the ban on smoking in companies and public transport. She did not stand for re-election in 2002 election.
Hermann is currently retired but still has several functions. She is a member of the Central Medical Review Board, she chairs the Foundation for General Social Work IJmond-Beverwijk and she is member of the board of the Foundation for Elderly Care in Velsen.