Born in Dubrovnik in a tradesman family, then a part of Austria-Hungary, Merćep started his primary education in Kladovo, Serbia and finished on the other side of the Danube in Turn-Severin (today Drobeta-Turnu Severin in Romania), He returned to his native town in 1878 where he worked as a merchant though his main interests lay in photography.
Since in Rusjan was already close to finishing his biplane EDA I that flew on 25 November 1909 – an event marked as the first flight of any South Slav.
Merćep continued work with Edvard's brother Josip and produced three more aircraft in which they trained pilots and gave many performances across Austria-Hungary.
After six months and many interventions of his friends he was out of prison only to find out that his hangar and workshop have been destroyed by the anti-Serb mob.
After the Great War, Merćep initiated the founding of aero club in Zagreb in 1925 and was one of the founders of the Aero-Club of the Kingdom of Serbs, Croats and Slovenes in the same year.