Næss was born in Germany in 1937 to German physician August Oskar German Raab (1901–1993) and Kirsten "Kiki" Dekke Næss (1907–2001), a Norwegian national whose brother was philosopher and mountaineer Arne Næss. His parents divorced after the war, and Næss moved to Norway with his mother where they both took her maiden name Næss.
By age 19 Næss had already made twenty first ascents of Norwegian mountains. In the seventies he returned to mountain climbing. In 1985 he led the first Norwegian expedition to Mount Everest, reportedly one of the more successful Everest climbs to have taken place.
Also participating was British mountaineer Chris Bonington.
According to police reports, Næss" anchoring equipment loosened from the porous mountainside, leading to a 103m fall. He was 66 years old.
