 After her ministerial ordination in 1985, she became the village pastor of Frielendorf-Spieskappel in the Schwalm-Eder-Kreis, together with her husband, from whom she was divorced in 2007.Käßmann earned her Ph.D. under Konrad Raiser, at the Ruhr University Bochum, with a thesis on the topic "Poverty and Wealth as an Inquiry into the Unity of the Church".In 1990, she was assigned to the Evangelical Church's volunteer service, and from 1992 to 1994, she was director of studies at the Evangelical Academy at Hofgeismar.