The victory came aboard the mare Greya, deflecting a strong challenge from Christian Kukuk and his Olympic gold medal partner Checker 47.
The American and the speedy mare won the $340,000 Longines FEI Jumping World Cup in Thermal, CA, his second WC victory this season.
The pair won the $200,000 UF Health Grand Prix CSI4* in a three-horse jumpoff – the US rider's third international victory in two weeks.
The Holiday & Horses CSI4* week at Wellington International concluded with the US rider scoring in the feature Grand Prix on Sunday.
The American was also awarded Leading International Rider honours at the event which ran at the Kentucky Horse Park, Oct. 29-Nov. 03.
The US rider opened Major League Show Jumping at Traverse City Horse Shows in the $181,170 event; Erynn Ballard 3rd with Ginger Ask.
Kent Farrington piloted the speedy mare to win the Longines FEI Jumping World Cup; Erynn Ballard was 10th with De Flor 111 Z Santa Rosa.
The action included the Rolex Grand Prix, Loire Region Derby and Nations' Cup Barrière as selectors get closer to picking Olympic teams.
The US rider won back-to-back Challenge Cups; two Canadians place top-10 in competitive class of 52 entries and a 12-horse jumpoff.
Kent Farrington and Landon score in the WEF Challenge Cup 4, while Canadians place third and win a class earlier in the day.