During the II World War, the castle was home of the Grafeneck Euthanasia Centre (German: NS-Tötungsanstalt Grafeneck), one of the main Nazi Germany's killing centres part of their Action T4 programme.

Built around 1560, the Grafeneck Castle served as a hunting lodge to the dukes of Württemberg.

In the 19th Century, it was used as the Forest Service and in 1928 the Samaritan Foundation acquired it, setting up a handicapped home.

In the times of National Socialism, the Grafeneck Castle served in as a killing center - the Nazi Euthansasieaktion (later T4 Action) killed 10,654 disabled and sick people through lethal injections and gas.

The French occupying forces returned the site in 1946/47 back to the Samaritan Foundation, whom reestablished it as a center for disabled and mentally ill people and still operates to this day.