The Frenchman, who moved to Ford after Volkswagen announced their shock exit from the competition in November, finished over two minutes clear of Finland's Jari-Matti Latvala with Estonian Ott Tanak third.
Ogier had inherited the lead when pacesetter Thierry Neuville crashed his Hyundai on Saturday's final stage and Ogier took a 47-second lead over fellow Ford driver Tanak into Sunday's four concluding specials.
He drove cautiously as snow fell along the Col de Turini mountain pass but eased to a fourth straight Monte Carlo victory -- the fifth of his career -- as organisers cancelled the penultimate stage due to fan safety concerns.
The decision came after Thursday's opening special was abandoned after New Zealander Hayden Paddon's Hyundai was involved in a fatal collision with a spectator.
While Ogier avoided trouble, Tanak suffered engine problems and incurred a 50-second penalty as he lost farther ground before finishing close to three minutes behind the winner.
"Of course I hoped to win from the opening race but to do it with such little preparation is incredible," said Ogier, who earned the Ford team's first victory since 2012.
