Kim, 17, was victorious in both the individual and team air pistol events in Incheon on Sunday.
The Korean prodigy, who took up the sport three years ago, edged out China's Pang Wei and compatriot Jin Jong-Oh in the men's 10 metre air pistol individual final.
Kim was also top of the podium in the 10m team event as host nation South Korea claimed gold with 1,744 points. China settled for silver while India took bronze.
In the women's individual fencing foil, South Korean defending champion Nam Hyun-hee won through to the semi-finals.
Nam defeated Yan Wai Liu of Hong Kong 15-4 in the quarters. Joining Nam in the final four are Lin Po Heung, Jeon Hee-Sook and Huilin Le.
Meanwhile, Malaysia advantaged to the semi-finals in the men's badminton, beating Nepal 3-0.
In the men's beach volleyball, 2010 gold medallists China accounted for Afghanistan 2-0 in Pool C action. Indonesia edged Sri Lanka 2-1 in the other Pool C clash.
In Pool F, Japan beat South Korea 2-0 and Oman defeated Kuwait by the same scoreline. In the women's draw, defending champions China downed hosts South Korea 2-0.