The castle dates back to a castle stable with a building yard built by Wilhelm von Rohr around 1397. Wilhelm's castle on the Hausberg - at the foot of which the castle is located - was besieged and destroyed by Duke Albrecht III in 1390. The later owners from the Zelking family - Erhard von Zelking acquired the shares in Leonstein in 1447 and 1459 - formed the Feichta valley castle from the castle stable and building yard. Count Georg Siegmund von Salburg acquired the castle and the Leonstein estate in 1629 from the Zelking family's inheritance. The Salburg family rebuilt Feichta in the Baroque style in 1724 and called it "New Leonstein".
At the end of 1919, the Upper Austrian state government bought the property from Count Theodor Salburg for 2,000,000 crowns. Count Schmidegg, who had already leased the castle from the Salburg family, stayed at the castle even after the change of ownership. From 1920, Leonstein Castle was a state property and belonged to the state forestry administration. The fermentation cellar of the Leonstein brewery was located in the building. Renovation and conversion work followed in 1938. The female labor service of the RAD (Reich Labor Service) was subsequently housed there; the Schmidegg couple had already died by this time. From 1944, the Wehrmacht used the building - for training courses, among other things. After the end of the war, the property returned to state ownership. Since November 1945, it has housed a state children's home.