The super-maxi finished in an official time of one day, 18 hours, 23 minutes and 12 seconds.
It set the previous record in 2005 of one day, 18 hours, 40 minutes and 10 seconds.
The line honours win adds to victories in 2005-08 and 2010.
Wild Oats skipper Mark Richards said breaking the record was a huge achievement.
"It was close, we only just made it but it's a great result for the whole team," he told Channel Seven.
"This boat is a great machine and we're very proud of it. Getting the record is a big thing and it's very satisfying.
"It's fantastic. It's a great result for the whole team so we are absolutely stoked."
As Wild Oats sailed up Hobart's Derwent River, the record looked out of reach with a weaker westerly slowing the yacht down.
"It was a very tricky night, the breeze died on us. It was very testing and we had to make a lot of sail changes, but it's all part of the Sydney-Hobart," said Richards.
"The crew have been together a long time and when the going gets tough they just get tougher."