Overbrook won the 1996 Kentucky Derby with the home-bred colt Grindstone and captured his second Breeders' Cup Juvenile that fall with Boston Harbor. In 1999 he won the 1999 Breeders' Cup Classic with Cat Thief. Active in the horse racing industry, William Young served as a director of the Breeders' Cup Limited. His daughter Lucy married renowned French horse trainer Francois Boutin and remains active in the industry. On June 9, 2009, William Young Jr., who assumed control of the Overbrook operation upon the death of his father, announced that his family would be selling the majority of their bloodstock. During the next few months Overbrook sold off its resident stallions then in September sold 48 yearlings for $6,644,000 and in November sold 148 horses for $31,760,000  including Honest Pursuit, a daughter of Storm Cat who sold for $3.1 million to Wertheimer et Frere. Young was a community leader in such organizations as the YMCA, Junior Achievement, Spindletop Research, the Red Cross, and the Cancer Drive. He was a University of Kentucky trustee and donated $5 million of his own money while helping raise additional funds to build a new library at the University of Kentucky that would be named the William T. Young Library in his honor. He further created a book endowment and campaigned for donations to fund it. At the time of his death the endowment was the largest of its kind in the United States. William Young was inducted into the College of Engineering Hall of Distinction in 1992. Appointed to the board of trustees of Transylvania University in 1967, he served as its chairman for twenty-three years from 1977 to 2000 and was a most important figure in the university's expansion and betterment. In 1985, William Young joined the board of historic Shakertown near Lexington and was appointed its chairman in 1990. In that role, he was instrumental in raising funds for important renovations needed to increase visitor revenues and as well he set up a program to insure the village's financial stability. Overall, William Young donated more than $60 million to various causes. His wife, the former Lucy Hilton Maddox, died in 2002 and he died in 2004. He was survived by a son, William T. Young Jr., and daughter, Lucy Young Hamilton.