The benchmark Korea Composite Stock Price Index (Kospi) added 4.57 points, or 0.15 percent, to close at 3,153.4 points.
Trading volume was moderate at about 605 million shares worth some 12 trillion won ($10.2 billion), with gainers outnumbering losers 531 to 322.
Foreigners bought a net 294 billion won, while institutions sold a net 142 billion won. Retail investors offloaded a net 183 billion won.
The Kospi opened higher as bargain hunters sought oversold stocks on expectations of a future price hike. But the trading turned choppy in the late morning as investors tried to digest the weak economic gauges.
South Korea's job growth slowed for the fourth straight month in August, largely due to the latest surge in COVID-19 cases and the toughest-ever virus curbs.
During the same month, the US consumer prices also showed the smallest gain in seven months, fanning concerns of slowing economic recovery.
The Kospi rebounded in the afternoon as investors increasingly pull optimism from the data.
"The weaker-than-expected consumer price in August turned out positive for the KOSPI by easing market worries about an early US tapering," Mirae Asset Securities analyst Park Gwang-nam said.
In Seoul, market kingpin Samsung Electronics added 0.52 percent to 77,000 won, but No. 2 chipmaker SK hynix closed unchanged at 107,500 won.
Internet portal operator Naver decreased 0.5 percent to 400,500 won, and its rival Kakao retreated 1.21 percent to 122,500 won. Pharmaceutical giant Samsung Biologics gained 2.52 percent to 936,000 won.
Top automaker Hyundai Motor moved up 0.24 percent to 209,500 won, but leading chemical firm LG Chem shed 2.18 percent to 718,000 won.
The local currency closed at 1,170.5 won to the US dollar, up 0.3 won from the previous session's close. (Yonhap)