Kladarin was born in Luščani, Yugoslavia on 3 March 1915.
In 1941, Kladarin entered the National Liberation Army and Partisan Detachments of Yugoslavia. During the Second World War, he was a battalion commander and also the commander of the Yugoslavia Banijskega Troop.
In 1950, after World War Two, he graduated at the Higher Military Academy Army and then held high-ranking positions such as Brigade Commander and Division Chief of Staff. Đuro Kladarin officially retired from his political career circa 1965.
- Various editions of The Europa World Year Book
- 1978 Vojna Enciklopedija (Volume 4), pg. 358