During the 15th century, there were considerable difficulties resulting from famines, failed harvests, and epidemics, From 1569 onwards, the Habsburg archduke Charles II of Austria initiated the rafting of timber down the Mur, which gained considerable importance for Zeltweg's history.

In 1848, Count Hugo Henckel von Donnersmarck, who came from Upper Silesia, decided to relocate his family's smeltery from Carinthian Frantschach-Sankt Gertraud to the site.

Zeltweg was detached from neighboring Fohnsdorf as a municipality in its own right and the first mayor, Heinrich Dillinger, was elected in 1875.

After the Austrian Anschluss in 1938, the Zeltweg ironworks were incorporated into the Reichswerke Hermann Göring conglomerate, employing numerous unfree labourers during World War II.

Since 1986, the palace has been owned by Anton and Ingrid Hartleb, who refurbished it and transformed it into a site for cultural and artistic events.

Furthermore, Austria's largest military airport, Zeltweg Airfield (Fliegerhorst Hinterstoisser) operated by the Austrian Air Force is located here, which was built in 1937.