Racing at age three in 1964, Prince Royal won his first three starts before finishing fourth in the Gran Premio d'Italia.
He ran in the Prix Royal-Oak in poor racing condition and was held back, finishing last to Baron Guy de Rothschild's winning colt, Barbieri.
Negotiations, which had been going on prior to the Prix Royal-Oak, saw American Rex Ellsworth purchase Prince Royal for a reported US$400,000 who turned him over to French trainer, Georges Bridgland.
In 1964, the Independent Timeform organisation awarded Prince Royal a rating of 134, making him the highest-rated three-year-old colt of the season ahead of The Derby winner Santa Claus.
[6] Prince Royal served stud duty at owner Rex Ellworth's breeding operation in Southern California's Chino Valley from 1965 through 1973.