»Rastat« was first mentioned in documents in 1074. Due to its strategically important location on the old Roman road from Aquileia over the Radstadt Tauern to Juvavum (Salzburg), Radstadt received town rights under Archbishop Rudolf von Hohenegg in 1289.
In the deep Middle Ages Radstadt became a booming centre of trade. During the time of the Peasant Wars, the town held out under Michl Gaismair (1525/26) against siege by 5,000 peasants, and in 1527 received the Great Letter of Freedom from Archbishop Matthäus Lang. After numerous occupations by Austrian, Bavarian and French troops, the town became in 1816 part of the Austrian Crown land of Salzburg.