He became the first Triple Crown winner in 25 years and his record-breaking victory in the Belmont Stakes, which he won by 31 lengths, is often considered the greatest race ever run by a thoroughbred racehorse.

Chenery later said that both owners hoped they would lose the coin toss,[9] which was held in the fall of 1969 in the office of New York Racing Association Chairman Alfred G. Vanderbilt II, with Arthur "Bull" Hancock of Claiborne Farm as witness.

On March 30, 1970, at 12:10 a.m. at the Meadow Stud in Caroline County, Virginia, Somethingroyal foaled a bright-red chestnut colt with three white socks and a star with a narrow stripe.

[29] His powerful hindquarters allowed him to unleash "devastating" speed and because he was so well-muscled and had significant cardiac capacity, he could simply out-gallop competitors at nearly any point in a race.

[23] Secretariat was known for his appetite — during his three-year-old campaign, he ate 15 quarts of oats a day — and to keep his muscles in good condition, he needed fast workouts that could have won many a stakes race.

At the start, a horse named Quebec cut in front of the field, causing a chain reaction that resulted in Secretariat being bumped hard.

"[44] Ten days later in the Hopeful Stakes, Secretariat made a "dazzling" move, passing eight horses within 1⁄4 mile to take the lead then drawing off to win by five lengths.

However, following an inquiry by the racecourse stewards, Secretariat was disqualified and placed second for bearing in and interfering with Stop the Music, who was declared the winner.

[48] He completed his season in the Garden State Futurity on November 18, dropping back early and making a powerful move around the turn to win by 3+1⁄2 lengths at 1–10 odds.

[52] In January 1973, Christopher Chenery, the founder of Meadow Stables, died and the taxes on his estate forced his daughter Penny to consider selling Secretariat.

The start was marred when Twice a Prince reared in his stall, hitting Our Native, positioned next to him, and causing Sham to bang his head against the gate, loosening two teeth.

[45] William Nack wrote: "Secretariat suddenly transcended horse racing and became a cultural phenomenon, a sort of undeclared national holiday from the tortures of Watergate and the Vietnam War.

[44][82] A large crowd had started gathering around the paddock hours before the Belmont, many missing the races run earlier in the day for a chance to see the horses up close.

[92] Secretariat next went to Saratoga, popularly nicknamed "the graveyard of champions", in preparation for the Whitney Stakes on August 4, where he would face older horses for the first time.

On race day though, he was beaten by the Allen Jerkens-trained Onion, a four-year-old gelding that had set a track record at 6+1⁄2 furlongs in his previous start.

[94] Despite Jerkens's reputation as the "Giant Killer," Secretariat's stunning loss can possibly be attributed to a viral infection, which caused a low-grade fever and diarrhea.

Returned to Belmont to point for the $250,000 Marlboro, the sport's pin-up horse looked bloody awful, rather like one of those sick paintings which betoken an inner theatre of the macabre.

Prove Out ran the race of his life that day: his time was the second-fastest mile-and-a-half on the dirt in Belmont Park's history despite the sloppy conditions.

Accordingly, Secretariat's last race was against older horses in the Canadian International Stakes over one and five-eighths miles on the turf at Woodbine Racetrack in Toronto, Ontario, Canada on October 28, 1973.

Despite the weather, some 35,000 people turned out to greet Secretariat in a "virtual hysteria.” His biggest opponents were Kennedy Road, whom he had beaten in the Marlboro Cup, and Big Spruce, who had finished third in the Man o' War.

[106] After the race, Secretariat was brought to Aqueduct Racetrack where he was paraded with Turcotte dressed in the Meadow silks before a crowd of 32,990 in his final public appearance.

[134] Inbreeding to Secretariat has also proven successful, as exemplified by numerous graded stakes winners, including two-time Horse of the Year Wise Dan, as well as sprint champion Speightstown.

[135] Secretariat's paddock at Claiborne Farm bordered three other stallions: Drone, Sir Ivor, and Hall of Fame inductee Spectacular Bid.

Secretariat did not pay much attention to Drone or Sir Ivor, but he and Spectacular Bid became friendly and occasionally raced each other along the fence line between their paddocks.

[139] An extremely large heart is a trait that occasionally occurs in thoroughbreds, hypothesized to be linked to a genetic condition, called the "x-factor", passed down in specific inheritance patterns.

[153] Due to Secretariat's enduring popularity, Chenery remained a prominent figure in racing and a powerful advocate for thoroughbred aftercare and veterinary research until her death in 2017.

"Paynter's popularity stems from his ability to battle and exceed expectations, making him the perfect choice as the recipient of this year's Vox Populi Award", said Chenery.

The film, starring Diane Lane as Penny Chenery, John Malkovich as Lucien Laurin, and Otto Thorwarth as Ron Turcotte, was written by Mike Rich, directed by Randall Wallace, and produced by Walt Disney Pictures.

[173] A fictionalized version of Secretariat appears in the animated series BoJack Horseman, wherein he is depicted as an anthropomorphic horse who is a world-class athlete, voiced by John Krasinski.

Before Secretariat's Triple Crown run, Bold Ruler was often categorized as a sire of precocious juveniles that lacked stamina or did not train on past age two.