Monarchos gave Oxley and his wife, Debby, North American racing's most coveted prize in 2001, the Kentucky Derby. Trainers John and Donna Ward, who handled the Oxley horses for more than 30 years, developed Monarchos, whose Derby time of 1:59.97 is the second-fastest in race history. The Oxley-Ward partnership produced a long list of stakes winners, led by champion female Beautiful Pleasure, a six-time Grade 1 winner who earned $2.7 million in her career. Other top horses campaigned by the Oxleys include Kentucky Oaks winner Gal in a Ruckus, Grade 1 winner and sire Sky Mesa, multiple graded stakes winner Darling My Darling, Beethoven, Dancinginherdreams, Strong Contender, Yes Dear Maggy, Stalwart, Pyramid Peak and Jambalaya Jazz. Oxley founded Oxley Petroleum, an oil and gas exploration firm based in his hometown of Tulsa, in 1962. He sold the company in May 2003 and has since started Oxley Resources LLC, a smaller-scale oil and gas exploration and production venture. He is the son of Hall of Fame polo player John T. Oxley, is the former chairman of the U.S. Polo Association and was elected to the Polo Hall of Fame in 2010.