[1] Ulrich's skills as a military commander are usually credited for the House of Celje's acceptance into the circles of the Central European high nobility in the second half of the 14th century.

He began his military career as a teenager when he joined the expedition of Hungarian king Louis the Great against the Venetians in Dalmatia in 1346, participating in the unsuccessful siege of Zadar.

[6] Despite beginning his career fighting against John Henry of Moravia in Tyrol, Ulrich eventually established strong ties with the Luxembourg rulers of Bohemia and Germany: in 1354, he took part in the expedition of the Holy Emperor Charles IV to Italy.

[7] Likewise, he had strong ties to Louis the Great of Hungary, fightzing on his side against Venice in 1354–55, in the siege of Treviso.

[9][10] In 1362-63, he fought on the side of the Habsburg duke Rudolf IV in Friuli and in Tyrol; in reward for his service, he was pawned with Kamnik in Carniola, and Žalec and Vojnik in Styria: the latter two would remain in the possession of his descendendants until the House of Cilli would die out in 1456.