Wachendorf was first mentioned as a bailiwick in 1190. On the site of Wachendorf Castle there was a knight's seat with a keep-like tower, originally with a late Gothic spire. This keep has been preserved as a central projection in the castle, now with a mansard roof. At least the lower floors of the central tower and significant sections of the wall of the north-western half of the manor house come from the medieval castle.
From 1287 onwards the Wachendorf family was documented as lords of the castle. In the late Middle Ages the property was a sub-lordship of the Duchy of Jülich. In 1434 Otto von Wachendorf gave the castle to Emmerich Brent von Vernich, who later gave it to Werner von Hompesch. The granddaughter Cecilie was married to Johann von Palandt. In the early 16th century the castle at that time came into the possession of the noble Palandt family. Johann von Palandt was one of the most important knights of the Jülich dominion. In 1628 witch trials under the lord of the castle Marsilius III led to a death sentence. von Palandt led to the death of 16 people. From 1687, the property was inherited by the von Hatzfeld family, who sold it in 1768 to Anna Maria von Hallberg, née von Holtzweiler, the mother of the Electorate of the Palatinate's ambassador Heinrich Theodor von Hallberg. In 1780, Wachendorf Castle was acquired by the Bavarian Major General Adolph Freiherr von Ritz. In 1877, the Euskirchen district administrator Johann Peter Schroeder sold the property and lands to Baron Solemacher-Antweiler, who had the castle rebuilt to its current form. His son sold the property to Paul von Mallinckrodt in 1896. The castle is now the private property of his descendants, the Müller von Blumencron family.