Based in California, Vietnam War veteran John Shirreffs began training Thoroughbreds in 1978.

He has won a number of stakes races with his most important coming in the 2005 Kentucky Derby when Giacomo scored a major upset.

In 2007, another Shirreffs-trained horse scored a major upset when Tiago, a half-brother to Giacomo (both out of the mare Set Them Free) won the Santa Anita Derby.

[1] Later he broke yearlings for Ed Nahem at Lakeview thoroughbred farm.

After that Shirreffs got his training license in 1978 and operated a small stable in Northern California.