Melas was born in Marseilles, France, the son of Michail Melas who was elected MP for Attica and mayor of Athens and brother of Vassileios Melas who was also an officer of the Hellenic Army. The Melas family was of Greek haute bourgeois descent.[1] Pavlos’ father was a wealthy merchant from Epirus.[2] At an early age Pavlos moved to Athens to study, and later joined the Army, graduating from the Hellenic Army Academy as an artillery lieutenant in 1891. In 1892, he married Natalia Dragoumi, the daughter of Kastorian politician Stephanos Dragoumis and sister of Ion Dragoumis. In 1895, the couple had a son named Michael and a daughter, Zoe.
He became member 25 of the Ethniki Etaireia and participated in the Greco-Turkish War of 1897.