Ismael "Milo" Valenzuela (born December 25, 1934 in McNary, Texas; died on September 2, 2009 in Arcadia, California) was a Thoroughbred horse racing Hall of Fame jockey. He was one of 22 children born to parents who had immigrated to the United states. Shortly after Ismael Valenzuela's birth, the family returned to their native Mexico. At age 14, Milo Valenzuela came back to the United States where he began working with quarter horses then launched his career as a jockey at a racetrack in Tucson, Arizona. He eventually began riding in California and would come to national prominence as a jockey competing for the American Triple Crown of Thoroughbred Racing.
Leading up to the 1958 Kentucky Derby, the California horse Silky Sullivan received much publicity for his habit of coming from very far behind to win races. It was the first time television played a major role in the publicizing of a racehorse and after Valenzuela won the Derby on board Tim Tam, the next day he was flown to New York City to make a guest appearance on CBS Television's The Ed Sullivan Show. Two weeks later, Valenzuela and Tim Tam won the Preakness Stakes but in the final leg of the Triple Crown they finished second at the Belmont Stakes after the horse fractured a sesamoid bone near the end of the race.
For over three years in the early 1960s Valenzuela was the regular rider of Kelso. On Kelso, Valenzuela won twenty-two important graded stakes races, passed Round Table to become the No. 1 money winner in thoroughbred racing history, and earned the most prestigious Horse of the Year award every year. In 1963, Milo Valenzuela was the recipient of the George Woolf Memorial Jockey Award given to a top thoroughbred jockey in North America who demonstrates high standards of personal and professional conduct, on and off the racetrack. In 1966 Valenzuela won the Canadian International Stakes and in 1968 history repeated itself when he again won the Kentucky Derby and Preakness Stakes with Forward Pass but fell short of winning the Triple Crown when they finished second in the Belmont Stakes.
After having won 2,545 races, Milo Valenzuela retired from racing to a home near Santa Anita Park. In December 1999 tragedy struck when his wife died suddenly of liver failure. Rosa Delia Valenzuela had been taking the doctor-prescribed drug Rezulin that a few months later was withdrawn from the market when the U.S. Food and Drug Administration concluded that Rezulin use had "possibly or probably" resulted in 90 liver failures, including 63 deaths and seven nonfatal organ transplants.
In 2008, Valenzuela was elected to the National Museum of Racing and Hall of Fame. In poor health, he was unable to travel to the annual induction ceremony on August 4 at Saratoga Springs, New York and was inducted in a special ceremony at Santa Anita Racetrack on June 22, 2008.
Seventy-four-year-old Ismael Valenzuela died on September 2, 2009 and was buried in the Live Oak Memorial Park Cemetery in Monrovia, California.
Milo Valenzuela had three brothers who also became jockeys as did his nephew, Pat Valenzuela.