After showing moderate form in 1905, he won The Derby on his seasonal debut at age three and then became the first British horse for twenty years to win France's most important race, the Grand Prix de Paris.

[4] Spearmint was sent to the Doncaster sales as a yearling and was purchased by Major Eustace Loder, who had been impressed by the colt when viewing him at Sledmere.

He made his debut in the £835 Great Foal Plate at Lingfield on 15 July, where he started at odds of 9/4 in a field of ten runners and won by a head in a time of 59.2 seconds, despite meeting interference in running.

On his final start of the year, he ran in the Richmond Nursery, a handicap race for two-year-olds at the Newmarket Houghton meeting in late October.

By spring, however, Admirable Crichton failed to make the expected progress between two and three, while Flair sustained a serious injury after winning the 1000 Guineas, leaving Spearmint as the stable's only viable Derby contender.

[10][11] When the results of this "private" trial became public, Spearmint began to attract serious support in the betting markets, and his odds fell from 20/1 on 15 May[12] to 11/2 a week later.

[14] Despite sweating freely in the hot conditions, Spearmint made a strong impression before the race as he demonstrated his "long-sweeping stride"[15] on the way to the start.

The early pace was exceptionally strong as the lead passed back and forth between Troutbeck and Picton, with Spearmint settled close behind.

The outsider Brisecoeur emerged as his only serious challenger, but Spearmint ran on strongly to win by half a length with Storm finishing third.

[21] Major Loder was personally congratulated by French President Armand Fallières, who also paid a visit to the racecourse stables to view the winner.