A first step for development of the King's Indian Defense was reached in the beginning of the 1930's. Until then it was thought that the huge space advantage in the four pawns attack gave White a free ride, but Max Euwe proved that Black's activity compensate for it in Benoni schemes with ...c5, ...e6, ...exd5.
In the beginning of the 1950's, beside Bronstein, several other players made a huge contribution to the boom of the KID : Gligoric, Najdorf, Geller, Szabo, to name a few.
After the tournaments of Mar del Plata 1953 (won by Gligoric, and which gave its name to an important and attractive variation) and Zurich 1953 (with Kotov's immortal game), the opening gained its new status and became not only "fashionable" but also "respectable".
Finally, Garry Kasparov was the first player to use the King's Indian as its main defense during a World Championship match when he successfully defended his title against Anatoly Karpov in Lyon in 1990.