Kent, 30, is based out of both New York and Wellington, Florida, and this was his first visit to Hickstead.
"I thought it was a really nice course today, and it was classically built," he said.
Kent got his ride Uceko from third-placed Leon Thijssen from the Netherlands. "He probably wishes he hadn't sold him to me now," said Kent.
In second, and best of the Brits, was Robert Smith and the talented stallion Talan.The first class today, the Royal International Accumulator, went to Saudi Arabia's Abdullah Al Sharbatly who won on board Lobster 43. The pair scored the maximum 65 points in a time of 54.55, almost three seconds quicker than their nearest rivals.
Sunday also saw the judging of the finale to six days of showing classes. The winner of the British Horse Society Supreme Horse title went to Jayne Webber on Jackie Beatham and Carol Bardo's riding horse champion Comberton Clancy, while the Dick Saunders Supreme Pony Championship was awarded to Poppy Marie Carter and her 128cms show pony Rotherwood Rainmaker.