Foreigners and individuals bought a combined 186 billion won ($127 million) worth of stocks, offsetting institutions' stock selling valued at 183.98 billion won.
Overnight, the Dow Jones Industrial Average rose 0.25 percent to 42,635.20, and the tech-heavy Nasdaq composite fell 0.06 percent to 19,478.88.
In Seoul, auto and tech stocks were lead gainers.
Hyundai Motor rose 1.87 percent, its affiliate Kia climbed 3 percent to 104,100 won, SK hynix jumped 3.2 percent to 201,000 won and LG Electronics climbed 0.12 percent.
Among decliners, Korean Air fell 0.22 percent, Jeju Air shed 0.9 percent and LG Energy Solution was down 1.2 percent.
The local currency was trading at 1,459.60 won against the greenback at 9:15 a.m., up 4.6 won from the previous session.