Harfouch was born in Suhl in Thuringia. She is the daughter of the teacher Wolfgang Meffert and his wife Marianne (née Kleber). Harfouch worked as a nurse in East Germany and studied acting in Berlin from 1978 to 1981. Her first husband was a Syrian computer scientist named Nabil Harfouch, with whom she has one daughter. In 1985 she married Michael Gwisdek, with whom she has two sons, Johannes and Robert Gwisdek. In 1994, she was a member of the jury at the 44th Berlin International Film Festival. She was previously married to Bernd Eichinger.