The origin of the castle's name is uncertain: local tradition has held that it derives from the extinct wild cattle aurochs (in Slovene, tur).
The first Turjak castle was built on the site as early as the late 11th century by the knights (later counts) von Auersperg.
On 20 May 1769, the allodial land ownership passed to his widow Elisabeth (nee Lichtenberg), while the fideicommiss went to his brother-in-law Josef Maria.
On 19 September 1943, the castle was taken by Partisans (ironically of the Prešeren brigade) after a lengthy battle with its garrison of Slovene Blue Guard detachments of Yugoslav Army in the Homeland.
In 2006, the president of Slovenia, Janez Drnovšek, founded the Movement for Justice and Development, a civil-society group, at a large rally at the castle.
Large Renaissance defensive towers (bastilles) at the points of the triangle are connected by residential wings.
As recently as the 1680s, the Valvasor engravings show a rectangular structure with small towers at only two corners and a large bastille at the eastern end.
This layout dates to the major rebuilding after the devastating 1512 earthquake, though some pre-16th century elements survive, notably the north wing and portions of the defensive walls.
Turjak Castle is fairly well known in Slovenia, in part for its colorful and turbulent history, which includes several grotesque vignettes: The castle is also known for its importance to the history of the Reformation in Slovene lands; its greatest claim to fame, however, is as the setting of one of Slovene national poet France Prešeren's most popular ballads, "Rosamund of Turjak" (Turjaška Rozamunda).