Under Gilbert’s tutelage, Gauff, 20, won the first major of her career in New York last year.
However, Emma Navarro, another American, defeated her in the fourth round this year.
“Coco, you have an incredibly bright future at just 20 years old, and I wish you nothing but continued success ahead,” wrote Gilbert on X. Gilbert also coached Andy Murray, Andy Roddick, and Andre Agassi, three past Grand Slam winners.
“I’m excited for the next chapter in my coaching career.”
Following a humiliating first-round loss at Wimbledon the previous year, Gauff brought Gilbert on board to work with Spanish coach Pere Riba.
Following that, Gauff’s fortunes took a turn for the better as she won 18 of her next 19 games during her home hard-court trip, culminating in titles in Washington, Cincinnati,, and New York.
How ‘learning curve’ for Gauff resulted in US Open title
Gauff splits with coach Gilbert
Securing a career-best 12 consecutive victories, including the US Open final victory over Aryna Sabalenka.
In November, Riba departed the team, leaving Gilbert as the only head coach.
Gauff has not made it to a final this year since January, when they defended the Auckland championship.
She advanced to the semi-finals of the Australian and French Opens before losing in the Wimbledon fourth round and reaching the same round of the US Open.
It was unclear if she would stick with Gilbert because of her weak serve and forehand, having committed 19 double faults against Navarro.
“Thanks to Coco and the entire team for an absolutely amazing summer run in 2023 and for 14 months of incredible team effort,” Gilbert, 63, said.