The benchmark Korea Composite Stock Price Index rose 7.55 points, or 0.32 percent, to close at 2,372.29.
Trade volume was light at 302 million shares worth 4.51 trillion won ($4.01 billion), with gainers outnumbering losers 441 to 346.
The local stock market opened higher as market sentiment was boosted by overnight gains on Wall Street, recovering from a loss caused by North Korea's missile provocation. On Tuesday, Pyongyang fired a missile that flew over Japan, fueling further tension on the Korean Peninsula.
"The market is recovering from a brief dip in the previous session, and North Korea's related market rout may subdue," said Kim Byong-yun, an analyst at NH Investment & Securities.
Samsung Electronics, the top market cap here, rose 0.26 percent to end at 2,310,000 won.
SK hynix, a major chipmaker, advanced 1.33 percent at 68,500 won, while shares of Hyundai Motor, South Korea's No. 1 automaker, backtracked 0.69 percent to end at 143,000 won on concerns over a protracted slump in China.
In contrast, LG Chem, the No. 1 chemical firm, jumped 3.12 percent to end at a yearly high of 380,000 won.
Oil refiners were also among gainers. SK Innovation, the No. 1 oil firm in the country, climbed up 1.36 percent to end at 186,000 won, and S-Oil, the No. 3 oil refiner, gained 3.66 percent to end at 127,500 won.
The local currency closed at 1,124.20 won against the US dollar, up 2.2 won from the previous session's close.
Bond prices, which move inversely to yields, ended higher. The yield on three-year Treasurys fell 2 basis points to 1.752 percent and the return on the benchmark five-year government bonds shed 1.7 basis points to 1.958 percent. (Yonhap)