In 1972, Rheingold was second by less than a head to Roberto in the Epsom Derby then after winning the Grand Prix de Saint-Cloud against older horses, finished off the board in the famous Benson & Hedges Gold Cup in which Roberto handed the great Brigadier Gerard his only defeat. The following year, Rheingold finished second in the King George VI & Queen Elizabeth Stakes to the great French filly, Dahlia. He won his second straight Grand Prix de Saint-Cloud under jockey Yves Saint-Martin then in the fall defeated the future French Horse Racing Hall of Fame filly Allez France to capture the Prix de l'Arc de Triomphe under the English jockey Lester Piggott.
Rheingold was retired after the 1973 racing season and stood at stud in Ireland from 1974 to 1979. Among his progeny, he was the sire of two-time Ascot Gold Cup winner, Gildoran and Noir et Or whose wins included the Grade I Grand Prix Prince Rose and Prix du Conseil de Paris.
In 1980 Rheingold was sold to a Japanese breeding operation where he died in 1990.