Martin Loewstroem Nyenget won silver, and the bronze went to Emil Iversen.
The trio of Norwegian skiers broke away from the pack early in the race as Nyenget pushed the pace and seemed poised to challenge for gold.
Klaebo tore away, however, on the final climb of the race, charging up the same hill where he has stranded competitors for other races in these Games.
Victory on Saturday for "King Klaebo", as fans call him, breaks US speed skater Eric Heiden's record of five gold medals from the 1980 Winter Games in Lake Placid, New York.
It marks the 11th career gold for the 29-year-old, giving him the most Olympic titles behind US swimmer Michael Phelps, who has 23.
Klaebo finished 8.9 seconds ahead of Nyenget, and 30.7 seconds ahead of Iversen, who had held with his teammates for much of the race and far outpaced other competitors.
Fourth-place finisher Theo Schely ended the race nearly three minutes behind Klaebo, and several racers dropped out of the competition altogether.
While Klaebo closed the race with a comfortable lead, he collapsed at the finish line in an unusual show of exhaustion for the skier who has dominated all six cross-country skiing men's events at these Games.
Norway’s Harald Oestberg Amundsen and Finland’s Iivo Niskanen, who had been in the front pack early on and were seen as medal contenders, dropped out on an uphill climb around the 37-minute mark of the race with about 15km completed.
Niskanen had been dealing with an illness all week, while Amundsen said a sickness before the Games hurt his performance.
"When I noticed I’m not going skiing for medals today, I figured it’s time to come to my senses so that I don’t kill myself out there," Niskanen said after dropping from the race.
Olympic medalists Federico Pellegrino of Italy and Ben Ogden of the United States also did not race due to illnesses.