Career
He learned the game around the age of ten and made rapid progress while studying Oriental Trade in Budapest. He also spent time in Vienna, the chess capital of the day, and this enabled him to get the high level practice necessary to take his game to the next level In 1910 he moved to Cologne and from there, travelled and toured extensively, mainly in the Americas, playing matches against local champions and exhibiting his legendary skills as a player of simultaneous blindfold chess.
At Havana in 1919 however, this impressive winning streak came to an abrupt end with a 5–0 loss to Capablanca.
Capablanca wrote that his own career peaked with this match. Kostic also played tournaments while in the United States, including New York 1916, Chicago 1918 and New York 1918, where he finished second behind Capablanca.
At Bled 1931, he finished in tenth place, but nevertheless outscored such luminaries as Maróczy, Colle and Pirc - the tournament was, at the time, regarded as one of the strongest in history. From 1923-1926, Kostic travelled all over the world, including Australasia, the Far East, Africa, India, and Siberia, demonstrating his exceptional skills, generating interest in chess and forging new links with people across the globe.
He was undoubtedly a brilliant publicist and ambassador for the game, although this probably prevented him from realizing his full potential as a player.
In the late 1920s, he made a return trip to the Americas. He represented Yugoslavia in four Chess Olympiads (London 1927, Prague 1931, Warsaw 1935, and Stockholm 1937), and in the 3rd unofficial Chess Olympiad at Munich 1936. During World World War II, Kostić (Orthodox Christian) was imprisoned in a concentration camp by a Nazi Steamship commander Schiller because he declined to participate in tournaments called "Free Europa" and to glorify the Nazi regime.
Afterwards, he played chess only in a more minor capacity.
Kostic was awarded the Grandmaster title by FIDE in 1950, on its inaugural list. He died in Belgrade in 1963, aged 76.