Duchess Marie Katharina was christened into the Roman Catholic Church with the names Marie Katharina Elisabeth Henriette Friederike Sophie Josephine et omnes sancti. She grew up with her family in the West German state of Baden-Württemberg in the south of the country.
Duchess Marie Katharina was married to Wolfgang von Wasielewski in a civil wedding on 17 March 1978 in Bonn. This was followed by a religious wedding four months later on 15 July 1978 in Biengen. After their marriage Duchess Marie Katharina and her husband initially lived together in Bonn before later moving to Munich where their two children were born, Natalia, in 1981 and Alexander, in 1983.
Through their daughter, who married Baron Constantin von Reitzenstein in 2010, Duchess Marie Katharina and her husband have four grandchildren, Helena, born 2011, Ferdinand, born 2013, Kyrill, born 2015 and Sophie, born 2018. Their son Alexander was married to Johanna Gering in July 2017.
Professionally Duchess Marie Katharina worked as a painting and sculpture restorer and her husband as a lawyer. Upon their retirement the couple moved out of Munich into a village in the Bavarian countryside.