There, Jimmy worked as his father's assistant but his career was interrupted when he joined the United States military during World War II.

After the war ended he returned to training horses, and in 1948 took over as head trainer from his father, who was appointed Calumet Farm's general manager.

Many fans and race experts believe Tim Tam would have won the Triple Crown had he not broken a sesamoid bone in his right foreleg coming down the home stretch in the Belmont Stakes, where he finished second.

As head trainer for Calumet Farm, Jimmy Jones trained seven champion horses and won 54 stakes races.

He bequeathed several million dollars to the hospital, where a new patient wing was erected with several pieces of memorabilia put on display in his memory.