He was born in Radeln, Transylvania (nowadays Roadeş, part of Buneşti commune, Romania) in 1729 and joined the Austrian army at age 17. He served in the Seven Years' War as aide de camp for Leopold Josef Graf Daun. He was promoted to colonel in 1781. He fought on the lower Rhine in 1794 and the middle Rhine in 1795. Melas was then commander in Bohemia.