As a yearling, Glenelg was purchased by
August Belmont for $2,000. Due to his size and temperament it was decided that he should not race as a two-year-old. To give him time to mature, he was not started until well into his three-year-old season, his first start being in the
Belmont Stakes. Belmont wanted Glenelg's stable-mate, Fenian, to win, so Glenelg was held back in second. He went on to the Jerome Stakes, beating Vespucius but lost to that colt a week later in the Annual Stakes. He then won the Travers Stakes and finished his three-year-old season with one more victory, giving him three wins and two seconds in five starts. Glenelg was generally considered the best three-year-old of 1869. During his four-year-old season, he was the Older Male Champion. Early in the year, he ran third in the Westchester Cup and then was third again to Helmbold and Hamburg in the Saratoga Cup, but he later beat Helmbold in Maturity Stakes. He also won the Excelsior Stakes, Breakfast Stakes, and Bowie Stakes, which rounded off his four-year-old campaign. At age five, Glenelg started as favorite in the Westchester Cup but lost and came up lame after the race. Sent home to recuperate, he never raced again. ==Stud career==