Born as Frederick, Lord of Žovnek (Sanneck) and baron of Savinja (Soune) in the Holy Roman Empire, he inherited vast estates in Carinthia, Carniola and Styria upon the extinction of the Counts of Heunburg.

Ulrich of Heunberg owned important estates in Carinthia, Carniola and Styria, while Agnes was the titular heiress of the House of Babenberg through her mother Gertrude of Austria.

After a protracted legal and military struggle, Frederick prevailed with the help of his brother-in-law Ulrich von Walsee, captain (governor) of Styria, who enjoyed the support of the reigning duke Otto the Merry.

In the early 1330s, he was named captain (governor) of Carniola and the Windic March, preparing the ground for a smooth transition of power from duke Henry of Bohemia, the last male member of the Gorizia-Tyrol dynasty, to the Habsburgs.

Shortly before his death, he took part of a diplomatic mission on behalf of Albert II, Duke of Austria and the Hungarian king Louis the Great to the papal court in Avignon.

Slovenian historian Milko Kos called Frederick "the first architect of the Celje glory", claiming that "he possessed all those abilities in statesmanship that would characterize his greatest successors".

[4] Frederick's fiefs and allods covered almost the entire territory of the former March on the Savinja (now firmly part of the Duchy of Styria), safe for scattered ecclesiastical lands.