A bay filly by Private Account out of Grecian Banner (by Hoist the Flag), she was the undefeated winner of 13 races and won $1,679,880 in the United States from 1986 to 1988. For this feat, she was voted the 1988 Eclipse Award for Outstanding Older Female Horse.
Personal Ensign began her racing career as a two-year-old in 1986 with Randy Romero as her regular jockey. He would be aboard her for all but one of her thirteen wins. In her first season, she won a maiden race as well as the prestigious Frizette Stakes at Belmont Park. A fracture to her pastern bone cut short her two-year-old season shortly before the Breeders' Cup Juvenile Fillies, a race she would have been favored to win.Dr. Bramlage had to insert five screws in her left hind leg. Many people were sure her racing career was over.
Returning to the races late in her three-year-old year, Personal Ensign resumed her winning ways, taking four more races, including two stakes. Her biggest win that year was the Beldame Stakes against older mares.
Personal Ensign shone in 1988, winning all seven of her starts. Her wins included the Shuvee Stakes, the Hempstead Stakes (by a whopping seven lengths), the Maskette Stakes, and Beldame Stakes—all prestigious Grade I races against fillies. At Saratoga, she defeated males in the historic Whitney Handicap. Her swan song was a nose victory over Kentucky Derby winner Winning Colors in the Breeders' Cup Distaff, a race that is often referred to as the most exciting finish in Breeder's Cup history.
Personal Ensign was retired following the Breeder's Cup as the first undefeated champion in American racing in over 80 years.
In September 2006, at the age of 22, Personal Ensign (after coming up barren from a mating with Forest Wildcat), was pensioned to the Hancock family's Claiborne Farm. Said Claiborne breeding shed manager, Charles Koch, "She's still in good shape, looks good, and gets around fine. She's just a little arthritic. She'll be spending time out in the field with other mares Korveya, Arabian Dancer, and Narrate."
In the Blood-Horse magazine ranking of the top 100 U.S. thoroughbred champions of the 20th Century, Personal Ensign was ranked No. 48.
Personal Ensign's last foal was a 2006 colt by Forest Wildcat.