Lexington began his racing career on May 23, 1853 in the Association Stakes which he won in two straight one-mile heats. Only four days later, he would win the Citizens’ Stakes which was raced at two miles and he won in three heats. He would end his 3-year-old season with a win in a race against one other competitor in which he won in two heats at three miles.
In 1854, Lexington began his rivalry with Lecomte who he would face three times. Lexington won his first start of the year in the Post Stakes in two heats at four miles beating three others including Lecomte. A week later, Lecomte would beat Lexington in two straight heats at four miles which would be his lone defeat in his short career. It was during this time that the mass-produced stopwatch was supposedly developed to count time in fractions for racehorses. Lexington would go on to set a new record of 7:19 ¾ in a win on April 2, 1855. A grandson of Lexington, Fellowcraft, would beat the record in 7:19 ½ in 1874. Lexington would win his final start which was over Lecomte in two straight heats at four miles on April 24, 1855.
Lexington was sired by Boston (who was a famous racehorse himself as he won 30 of 35 starts) and like his sire went blind during his later years. Lexington was retired after he started showing symptoms of blindness in 1855 and went to stud duty that same year. The following year, he was purchased by R. A. Alexander for a record $15,000 and he was transferred to Woodburn Farm where he lived out the rest of his life.
Among the many feats by Lexington as a sire are his sons and daughters won nine of the first 15 runnings of the historic Travers Stakes at Saratoga Race Course. Of those Travers Stakes winners, three of them won the Preakness Stakes: Tom Ochiltree, Shirley and Duke Of Magenta. The Woodlawn Vase, the trophy of the Preakness Stakes, is modeled after Lexington. Including Duke Of Magenta, three of those Travers winners also won the Belmont Stakes: Harry Bassett, Kingfisher and General Duke.
At 15.3 hands, Lexington was described as a horse with ideal conformation and his disposition was excellent. After his death, his skeleton was donated to the Smithsonian Institution and is now at the International Museum of the Horse at the Kentucky Horse Park in Lexington, Kentucky. Lexington, along with his sire Boston, would be in the first group of horses inducted into the National Racing Hall of Fame in 1955. The Lexington Stakes at Keeneland Race Course is named in honor of this famous racehorse.