May 31, 1910 - January 4, 1946: Age 35
The name may sound familiar: George Woolf was played by real-life jockey Gary Stevens in the 2003 film Seabiscuit. Woolf is the Canadian jockey who became Seabiscuit's main rider after Red Pollard, the Tobey Maguire character, was injured.
Woolf was nicknamed "The Iceman" because his nerves were so steady that he would often take a nap before a race, instead of pacing and fretting. The most famous race he won was between Seabiscuit and triple-crown champion and favourite, War Admiral, in 1938.
Dubbed the "Match of the Century", it was discussed for many months in the media before it actually took place. Woolf and Seabiscuit's trainer approached the race strategically. Head-to-head races are usually run by fast starters, and Seabiscuit was known as a "pace stalker", sticking with the pack before a late acceleration. War Admiral, a much larger and stronger horse, was known as a fast starter. The trainer, knowing this, chose to secretly condition him to run against type, instilling an automatic burst of speed at the sound of the start bell.
With Woolf riding him, Seabiscuit burst ahead and led for the first half of the race. War Admiral slowly narrowed the lead, and for a long time they were head to head, to the great excitement of the crowds. In fact, Woolf was easing up on the horse, allowing him to see his opponent. In the final stretch, he asked for more, and got it: Seabiscuit won that race by four lengths, an unimaginable lead against such a formidable rival. You can see the whole race right now, here, on YouTube.
Woolf was a diabetic, and suffered greatly from the constant rapid dieting necessary to meet the weight requirements of his profession. While in a race in 1946, he slipped from his saddle head first on the ground. The other jockeys and track stewards reported that nothing happened that would cause such a fall; it is likely it resulted from dizziness or fainting spell due to the diabetes. He was taken to hospital with a concussion and died the following day at the age of only 35.
Sources: Wikipedia, Find-a-Grave