Gabart, 29, finished in 78 days, 2 hours, 16 minutes and 40 seconds, breaking the previous record set in 2009 by six days.
Gabart would have finished sooner but his arrival at Les Sables D'Olonne was delayed by bad weather, Radio France Internationale said.
Frenchman Armel Le Cleche was on course to take second place late Sunday.
It was the seventh edition of the Vendee Global and the first for Gabart. He was already five days ahead of the record pace set by Michel Desjoyeaux in 2009 by the time he crossed the Equator.