The benchmark Korea Composite Stock Price Index edged up 2.94 points, or 0.14 percent, to 2041.74. Trading volume was moderate at 426 million shares worth 4.8 trillion won ($4.3 billion), with gainers outnumbering decliners 485 to 348.
The index opened lower, but it moved into positive terrain, apparently tracking Wall Street gains.
US stocks rose following the country's announcement that its gross domestic product advanced 3.1 percent in the first quarter, which is above Wall Street projections of 3 percent. The Dow Jones industrial average gained 0.17 percent, while the tech-heavy Nasdaq moved up 0.27 percent.
The Bank of Korea kept the key rate steady at 1.75 percent, but prospects for a rate cut grew after one board member cast a dissenting vote.
"The BOK said it is closely monitoring developments in the United States-China trade dispute," Kim Sang-hoon, an analyst at HI Investment & Securities, said. "But it kept the stance that the Korean economy is recovering."
Foreigners picked up a net 206 billion won worth of local stocks, while institutions and individuals dumped a net 152 billion won and 62.8 billion won worth of local stocks, respectively.
Market bellwether Samsung Electronics edged down 0.12, while No. 2 chipmaker SK hynix slid 0.91 percent.
Carmakers were weak, with No. 1 player Hyundai Motor losing 0.74 percent. Kia Motors plunged 4.49 percent and auto parts maker Hyundai Mobis lost 1.81 percent after US President Donald Trump announced that his administration will impose 5 percent tariff on goods coming from Mexico. Both Kia and Hyundai Mobis have plants in Mexico.
But pharmaceutical firms were bullish, with Celltrion gaining 2.15 percent and Samsung BioLogics shooting up 5.82 percent.
Chemical companies were also strong, with top player LG Chem advancing 1.68 percent and Lotte Chemical inching up 1.18 percent.
The South Korean won closed at 1,190.90 won against the US dollar, down 2.10 won from Thursday's close.
Bond prices, which move inversely to yields, closed higher. The yield on three-year Treasurys fell 3.9 basis points to 1.587 percent, and the return on benchmark five-year government bonds dropped 4.6 basis points to 1.605 percent. (Yonhap)