In 1919, Man o' War won 9 of 10 starts, including the Hopeful Stakes and Belmont Futurity, then the most important races for two-year-old horses in the United States.

Man o' War was not entered in the 1920 Kentucky Derby because his owner, Samuel Riddle, did not believe in racing at the distance of ten furlongs (2,000 m) so early in a young horse's career.

[4] Man o' War was the second foal out of Mahubah, a lightly raced mare by English Triple Crown Champion Rock Sand.

[8] At maturity, Man o' War stood 16.2 1⁄2 hands (66.5 inches, 169 cm), with prominent withers and a high croup, but was sometimes faulted for a dipped back that grew more pronounced with age.

[15] He won his first race by six lengths, then three days later was entered in the Keene Memorial Stakes at a distance of 5+1⁄2 furlongs (1,100 m) on a muddy track at Belmont Park.

With an eighth of a mile remaining, jockey Johnny Loftus urged him to run and the horse responded by pulling away from his rivals to win by three lengths.

[20] In the Sanford, most sources state that Man o' War was still circling with his back to the starting line when the barrier was raised (though some accounts say he was turned only slightly sideways).

Dempsey of The Daily Racing Form wrote, "Without attempting to detract from the merits of [Upset's] performance, Man o' War proved himself in the running unquestionably the best.

It was Upset's advantage at the start, coupled with 15 pounds weight concession, a perfect ride he received from Knapp and his success in saving ground on the stretch turn that brought his triumph over Man o' War.

"[17] Man o' War gained his revenge with a victory in the Grand Union Hotel Stakes on August 23, beating Upset by two lengths with Blazes in third.

Journalists, horsemen, and fans agreed that Man o' War had to be considered as one of the greatest American horses of his age, and they compared him favorably to the unbeaten Colin.

He decided not to enter him in the Kentucky Derby because it was run only a few days before his preferred target, the Preakness Stakes, which was held close to the Riddle farm where Man o' War had spent the winter.

Running as he pleased, Man o' War won by slightly more than a quarter-mile – the official margin was 100 lengths – while setting a world record of 2:40 4/5 for a mile and five-eighths.

Beckwith later called it "the most astounding display of arrogant annihilation", adding, "[Man o' War] was like a big red sheet of flame running before a prairie wind".

[43] The New York Times commented, "at Belmont Park yesterday [Man o' War] gave what was undoubtedly the greatest exhibition of speed over a considerable distance of ground ever witnessed anywhere.

"[42] Man o' War's next start was the Jockey Club Gold Cup on September 12, the first time he entered a race open to older horses.

The connections of Exterminator, another future Hall of Famer, were also considering the race but bypassed it because, under the weight-for-age conditions of the Gold Cup, he would have had to concede Man o' War five pounds.

Although it was declared a hollow victory by The New York Times, Man o' War still set an American record for 1+1⁄2 miles of 2:28 4/5, breaking the existing mark by 4/5 seconds.

Man o' War faced an early challenge from Blazes, then turned back a late run by Wildair to win by 1+1⁄2 lengths while breaking the track record by 1⁄5 seconds.

[48] There were no formal awards for American Horse of the Year at the time, but Man o' War was informally acknowledged as such in a retroactive poll of turf writers.

[57] In May 1922, he was moved to Faraway Farm, a property on Huffman Mill Pike outside of Lexington that had been jointly purchased by Riddle, his wife's niece Sarah Jeffords and her husband, Walter.

In late 1936 or early 1937, the Riddle horses were moved to an adjacent property, also called Faraway Farm, where Man o' War spent his final years.

Tiznow, Tourist, Da' Tara, In Reality, Desert Vixen, Honour and Glory, Bal a Bali, Skywalker and Bertrando are all sire-line descendants of Man o' War.

[9] Female line descendants from Man o' War include Eight Thirty, Stymie, Nijinsky, Sword Dancer, Pavot, Riverman, Jim French, Sir Ivor and Kelso.

[62] War Admiral was also a leading broodmare sire, especially when crossed with the influential mare La Troienne and his name can be found in many modern pedigrees through such horses as Seattle Slew, Buckpasser and Dr.

[85] He was originally interred at Faraway Farm, but in the early 1970s, he was re-interred at a new burial site at the Kentucky Horse Park, where his grave is marked with a statue by American sculptor Herbert Haseltine.

[87][88][10] ESPN ranked Man o' War as number 84 on their list of the top North American athletes of the 20th century, compiled for the SportsCentury documentary series.

[10] His stall door was loaned to the National Museum of Racing and Hall of Fame in Saratoga as part a special exhibit, "Man o' War at 100", that opened on March 29, 2017.

[97] In the 1970 motion picture M*A*S*H, the character Trapper John makes the apocryphal claim that a necropsy performed upon Man o' War following his death revealed that he was a homosexual horse, despite his prolific breeding history.

Fair Play inherited a difficult temperament from Hastings, and his disposition was completely soured after an unsuccessful period spent racing in England.