Oh, 44, reached the summit of the 8,091-meter Annapurna, the 10th highest peak in the world, without oxygen at 6:16 p.m. (Korean time), 13 hours and 16 minutes after she left the last camp around 5:00 a.m.
"Thank you, Thank you," she said in a tearful voice on arriving at the top of Annapurna.
She is the only woman to succeed in scaling all of the globe's 14 highest mountains exceeding 8,000m, which are all located in the Himalayan region.
Oh achieved the feat 13 years after she first climbed the 8,035m Gasherbrum II, one of the 14 "eight-thousanders," in July 1997.
Oh, who quit her job at the Seoul Metropolitan Office of Education in 1993 to pursue a mountaineering career, climbed Mount Everest, the world's highest peak at 8,848m, in 2004.
Oh conquered Annapurna, considered one of the most dangerous peaks in the world, on her second attempt, as she gave up her first push last October due to inclement weather.
Oh's feat surprised the world's mountaineering community, as she has a relatively small build of 50 kilograms and 154 centimeters.
Reflecting the Korean people's enthusiasm over her historic expedition, Korea's public broadcaster KBS sent its camera staff to accompany her for live coverage of her ascent on Tuesday.
Edurne Pasaban of Spain unsuccessfully competed with Oh to earn the distinction of becoming the first woman to climb all 14 highest peaks. The Spanish woman reached her 13th peak, the Annapurna, earlier this month and has Mount Shisha Pangma left to conquer.
Some have questioned whether Oh had actually reached the summit of Mount Kanchenjunga, the world's third-highest, in May last year, citing a picture taken at the top, in which it was too cloudy to recognize where she stood. She dismissed the accusation as groundless.
"I can say that I have stood at the summit of Mount Kanchenjunga," she said at a press conference in Seoul late last year. "It was bad weather. Three sherpas told me that I reached the top and one of them took the picture."
여성 최초 히말라야 14좌 완등
산악인 오은선이 27일 오후 6시 15분 여성 최초로 히말라야 8000m 급 14좌 완등에 성공했다.
지난 25일 정상에 오르려다 기상 여건이 좋지 않아 도전을 미룬 오 대장은 10시간이 넘는 강행군 끝에 캠프4에 도달했다.
휴식을 취한 등정대는 27일 오전 3시께 등정에 나서 16시간 만에 정상 등정에 성공했다.
오 대장은 애초 캠프를 전진시키면서 정상에 접근하는 등산 방식인 극지법으로 오르려고 했으나 기상 악화로 일정이 늦어지자 캠프를 건너뛰며 속공으로 정상을 공략하기로 계획을 수정했다.
강한 체력과 폐활량이 뒷받침돼야 할 수 있는 일이다.
한편 여성 최초 14좌 완등 타이틀을 놓고 오 대장과 경쟁하던 에두르네 파사반(36.스페인)은 지난 17일 안나푸르나 등정 후 최근 네팔에서 티베트로 넘어갔다.
14좌 완등에 시샤팡마(8천27m)만 남겨 둔 파사반은 시샤팡마 베이스캠프에 머물며 등정 시점을 논의 중인 것으로 알려졌다.
