[1] Born in Chula Vista, California, Whittingham began working around race horses at a young age and was eventually taken on as an assistant by Hall of Fame trainer Horatio Luro.

During World War II, his career was interrupted by service with the United States Marine Corps.

At war's end, he returned as an assistant trainer until 1950, when he set up his own stable to take on the training of horses for various owners.

Among others, he trained Daryl's Joy, champion New Zealand two-year-old, winner in Australia wfa championship W S Cox Plate, Victoria Derby, Oak Tree International (USA), Cougar II, the 1972 U.S. Champion Turf Horse, Kennedy Road, the 1983 Canadian Horse of the Year, and for a time, Exceller.

In 1986, at the age of 73, he became the oldest trainer to win the Kentucky Derby, then won the prestigious race again three years later.