The benchmark Korea Composite Stock Price Index rose 24.35 points, or 1 percent, to close at 2,458.16. Trade volume was moderate at 193 million shares worth 5.6 trillion won ($3.07 billion).
The local stock market opened higher, tracking a strong lead from Wall Street overnight.
The last time the KOSPI hit a record high was July 24, when it stood at 2,451.53.
Hong Choon-wook, an analyst at Kiwoom Securities, said the local stock market was positively affected by a steady weakness in the US dollar and a modest rise in oil and other commodity prices.
Lee Young-kon, a Hana Financial Investment analyst, said expectations about a global economic recovery have driven investors' appetite for local stocks.
Foreign investors scooped up a net 444.9 billion won worth of local stocks.
Samsung Electronics rose 3.48 percent to end at 2,732,000 won, and SK hynix, a global chipmaker, gained 0.45 percent to 89,100 won.
Naver, the operator of the country's top Internet portal, shed 0.66 percent to 751,000 won.
Hyundai Motor rose 2.65 percent to 155,000 won, and its smaller affiliate Kia Motors climbed 1.88 percent to 32,550 won.
The local currency closed at 1,135.25 won against the US dollar, up 0.35 won from the previous session's close.
Bond prices, which move inversely to yields, closed higher. The yield on three-year Treasurys fell 0.9 basis point to 1.929 percent and the return on the benchmark five-year government bond declined
0.7 basis point to 2.135 percent. (Yonhap)