Trainer John Shirreffs will forever be linked to equine sensation Zenyatta, owned by Jerry and Ann Moss. Zenyatta was voted Horse of the Year in 2010 and she is the only female ever to win the Breeders' Cup Classic (2009). Zenyatta also was awarded Champion older female honors for three consecutive years (2008, 2009, 2010). Shirreffs made history in 2009 when he saddled both the winners of the Breeders' Cup Classic (Zenyatta) and the Ladies’ Classic (Life is Sweet). Zenyatta became the first Eclipse Award champion for Shirreffs when she won the champion older female award in 2008. In 2005, Shirreffs saddled longshot Giacomo, also owned by the Mosses, to win the Kentucky Derby. His wife, Dottie, is their racing manager.
Shirreffs, who bases his 50-horse stable at Santa Anita Park, grew up dividing his time between Port Washington on Long Island, N.Y., and New Hampshire, where he spent time around horses on his family's farm near Neufields. A Vietnam War veteran, Shirreffs served in the Marine Corps and, after being discharged, he settled in California after meeting Henry Freitas, then manager of Loma Rica Ranch.
Shirreffs took out his trainer's license in 1978, operating a small stable in Northern California. He moved south as an assistant to the late Brian Mayberry and Bill Spawr. In 1994, Shirreffs became the private trainer for Ed Nahem and Marshall Naify's 505 Farms until Naify's death in 2000. Shirreff's first stakes winner was Jade Ring, winner of the 1980 John Peri Stakes at Stockton. Other notable horses trained by Shirreffs include After Market, Tiago, Zardana, Harmonious, Mr. Commons, Gormley, and Keri Belle.