Born Krikor Aslanian in Switzerland or in Istanbul, according to different sources, Aslan made his professional debut at 18 as a vocalist and drummer with a Paris dance band, then launched an acting career under the name of Koko Aslan. His first film appearance was in Feux de joie (1938). He became an indispensable feature in many British and American films, usually playing foreigners - Russians, Frenchmen, Italians, Germans, Albanians and Middle Easterners - with equal finesse.