Katharina's parentage and family history have not been explored, but in 1986 she is seen as a headstrong pupil at the Winden high school. She is dating the rebellious young Ulrich Nielsen, provoking jealous rage in Hannah Kahnwald.
It is mentioned that she and Ulrich once tied Regina Tiedemann to a tree in the forest and left her there as a prank. Later, wrongly suspecting Regina has accused Ulrich of rape, Katharina attacks her in the forest, only driven off when a mysterious stranger, later revealed as Boris Niewald, appears brandishing a gun.
Katharina is now principal of the school and mother of three. She remains a fierce woman to contend with, but the enemies she made in her youth have not forgiven her: Regina attacks her after a school performance, and Hannah carries on an affair with Ulrich.
She discovers Ulrich's many calls to Hannah and drives to the Kahnwald household to confront her, not knowing that Ulrich had earlier broken off the affair. The embittered Hannah lies and says Ulrich was planning to leave Katharina—something his disappearance seems to confirm.