Susan Roy raced Wilko as a two-year-old in the United Kingdom, where he won two races and had his best result in a stakes race with a second-place finish in the Vintage Stakes to Shamardal who would become that year's European Two-Year-Old Champion. Wilko also ran third in the Superlative, Royal Lodge and Chesham Stakes. At the beginning of October 2004, American businessman J. Paul Reddam purchased a 75% interest in the colt.
Wilko was then sent to the United States to run in the Breeders' Cup Juvenile, held that year at Lone Star Park in Grand Prairie, Texas. Racing on dirt for the first time in his career, Wilko was ridden by British-based jockey Frankie Dettori. The field included the betting favorite Roman Ruler who had won the Best Pal and Norfolk Stakes, plus Afleet Alex who had won the Sanford Stakes and the Grade I Hopeful Stakes. Given little consideration by bettors, Wilko was sent off as a 28-1 long shot but won by a length over Afleet Alex. He was the first British-trained colt to win the race, and the third European after Arazi and Johannesburg.
On his next start, and the last of 2004, he ran third in the Hollywood Futurity behind runner-up Giacomo and winner Declan's Moon who would be voted that year's American Champion Two-Year-Old Colt.
In 2005, Wilko made six starts without a win then in 2006 went winless again but finished a solid second to Electrocutionist in the Dubai World Cup. He returned to racing in 2007 but fared poorly and was retired in August. In September, Wilko was acquired by Frank Stronach's Adena Springs breeding operation and will stand at stud at their Ocala, Florida facility where his sire Awesome Again is also located.