The Sherpa, 39-year-old Pemba Dorje, summited in a time of 12 hours 45 minutes, the Nepalese tourism ministry said.
The previous record was 16 hours 56 minutes, set in 2000 by legendary Sherpa Babu Chhiri who died after falling into a crevasse on Everest the following year.
The 39-year-old Dorje, making his 10th ascent of Everest, set out from Base Camp at 5 p.m. Thursday and climbed through the night, reaching the top at 5:45 a.m. Friday.
Unlike Chhiri, Dorje used bottled oxygen from South Col, the ministry said in a statement.
He wore his native Sherpa dress when he stood on the earth’s highest pinnacle.
Before returning "in high spirits" to South Col, Dorje placed a photograph of Nepalese King Gyanendra, Queen Komal and Crown Prince Paras on the summit, the statement said.
Dorje, a high altitude guide, was a member of the Belgium "Dream Everest 2003 Expedition," the ministry said.
His task was made easier because ropes and ladders had already been put in place by scores of climbers who have been tackling Everest in recent days.
Dorje was followed half-an-hour later on to the summit by another member of the team, Da Tshri, 26, who had set out from South Col.
Yesterday’s record followed one set Thursday when Japanese climber Yuichiro Miura became the oldest man ever to stand at the roof of the world.
Miura, aged 70 years and 222 days, broke the record of compatriot Tomiyasu Ishikawa, who summited last year at the age of 65 years and 176 days.
At least 53 mountaineers summited on Thursday, the tourism ministry announced, revising an earlier figure of 41.
It said Nepalese journalist Ang Chhiring Sherpa, 28, was among those who had crowded the peak of the mountain known in Nepal as Sagamartha on Thursday.
"Ang Chhiring spent 10 minutes at the summit, during which time he hoisted the flag of the Nepal Journalists Federation and placed a photo of Lord Buddha on the summit before descending to South Col," the statement said.
A total of 25 teams are hoping to conquer the world’s highest mountain to celebrate the historic first ascent by Tenzing Norgay Sherpa and Sir Edmund Hillary on May 29, 1953.
Massive celebrations are planned in the Nepalese capital Kathmandu on May 29, during which all the successful summiteers will be awarded special medals by King Gyanendra.