Which Kentucky Derby winners had the best careers after the race?

In most cases, the career of a Kentucky Derby (G1) winner doesn’t end on the first Saturday in May.

To the contrary, Kentucky Derby winners normally continue racing and often enjoy additional on-track success before retiring to stud, where they sire future generations of racehorses.

Determining which Kentucky Derby winners enjoyed the best post-Derby careers is subjective and depends on which achievements one values most—big wins, high earnings, championship titles, success at stud, etc.

That said, we’ll consider all these factors to reach evidence-based conclusions regarding the best post-Derby careers of Kentucky Derby winners.

Research methodology

We’ll consider half a dozen broad accomplishments in our analysis. Each achievement has been available to either all or the majority of Kentucky Derby winners, allowing us to compare which horses checked off the most boxes.

From there, we can apply a bit of subjective judgment to determine which Kentucky Derby winners enjoyed the best careers after the race.

Since we’re analyzing the best post-Derby racing and stud careers, we won’t consider accomplishments achieved prior to Kentucky Derby Day. Secretariat may have been Horse of the Year as a two-year-old, but that achievement carries no weight in our analysis.

Data analysis

Kentucky Derby winners enshrined in the Hall of Fame

A total of 41 Kentucky Derby winners have been inducted into the National Museum of Racing’s Hall of Fame: Aristides, Hindoo, Ben Brush, Old Rosebud, Regret, Exterminator, Sir Barton, Zev, Black Gold, Reigh Count, Gallant Fox, Twenty Grand, Cavalcade, Omaha, War Admiral, Johnstown, Whirlaway, Count Fleet, Assault, Citation, Swaps, Needles, Tim Tam, Carry Back, Northern Dancer, Majestic Prince, Riva Ridge, Secretariat, Foolish Pleasure, Seattle Slew, Affirmed, Spectacular Bid, Genuine Risk, Alysheba, Winning Colors, Sunday Silence, Silver Charm, Smarty Jones, California Chrome, American Pharoah, and Justify.

Kentucky Derby winners who swept the Triple Crown

Winning the Triple Crown is the greatest achievement in U.S. horse racing. Sweeping the Kentucky Derby, Preakness (G1), and Belmont (G1) isn’t easy, and since 1919, only 13 horses have done so: Sir Barton, Gallant Fox, Omaha, War Admiral, Whirlaway, Count Fleet, Assault, Citation, Secretariat, Seattle Slew, Affirmed, American Pharoah, and Justify.

Kentucky Derby winners who set earnings records

Nine Kentucky Derby winners have ranked as the highest-earning Thoroughbred to ever compete in North America: Zev, Gallant Fox, Whirlaway, Assault, Citation, Affirmed, Spectacular Bid, Alysheba, and California Chrome.

Kentucky Derby winners who earned Horse of the Year honors

A total of 30 Kentucky Derby winners have either been voted or recognized retrospectively as U.S. Horse of the Year in the year they won the Derby and/or in a subsequent year: Meridian, Old Rosebud, Regret, Exterminator, Sir Barton, Zev, Reigh Count, Gallant Fox, Twenty Grand, Cavalcade, War Admiral, Whirlaway, Count Fleet, Assault, Citation, Swaps, Secretariat, Seattle Slew, Affirmed, Spectacular Bid, Spend a Buck, Ferdinand, Alysheba, Sunday Silence, Charismatic, California Chrome, American Pharoah, Justify, Authentic, and Sovereignty.

Whirlaway, Affirmed, and California Chrome each earned two Horse of the Year titles following their Kentucky Derby triumph.

Kentucky Derby winners who became leading sires

Half a dozen Kentucky Derby winners have ranked as North America’s leading sire by progeny earnings in one or more years. They are Ben Brush, War Admiral, Count Fleet, Northern Dancer, Seattle Slew, and Thunder Gulch.

* Northern Dancer topped the 1977 sire rankings compiled by The Blood-Horse, which counted international earnings in addition to domestic earnings. 

Kentucky Derby winners who sired Kentucky Derby winners

A dozen Kentucky Derby winners have proven successful enough as stallions to sire one or more Kentucky Derby winners. Halma, Bubbling Over, Reigh Count, Gallant Fox, Bold Venture, Count Fleet, Pensive, Ponder, Determine, Swaps, Seattle Slew, and Unbridled.

Conclusions

In terms of post-Derby racing accomplishments, the exploits of Hall of Fame inductees Affirmed and Whirlaway set the standards by which all others are measured.

Following their Derby triumphs, Affirmed and Whirlaway both won the Preakness and Belmont to sweep the Triple Crown. Both earned Horse of the Year honors at age three and repeated the title at age four. Both retired as the richest horse on record, and Affirmed became the first to crack the $2 million plateau. Both won a bevy of major stakes races post-Derby, with Affirmed winning half a dozen Grade 1s at age four while Whirlaway took the Pimlico Special in a rare walkover.

When combined racing and breeding achievements are considered, the post-Derby exploits of Seattle Slew trump all. After winning the Preakness and Belmont to sweep the Triple Crown and earn Horse of the Year honors, Seattle Slew returned at age four to win the Woodward (G1) and Marlboro Cup H. (G1), defeating Affirmed in the latter race. He earned champion older male honors and joined the Hall of Fame a few years later.

When combined racing and breeding achievements are considered, the post-Derby exploits of Seattle Slew trump all. After winning the Preakness and Belmont to sweep the Triple Crown and earn Horse of the Year honors, Seattle Slew returned at age four to win the Woodward (G1) and Marlboro Cup H. (G1), defeating Affirmed in the latter race. He earned champion older male honors and was inducted into the Hall of Fame a few years later.

Then Seattle Slew embarked on a tremendous stud career. He led all North American stallions by progeny earnings in 1984, the year his son Swale won the Kentucky Derby and Belmont. All told, Seattle Slew sired over 110 stakes winners, including the breed-shaping 1992 Horse of the Year and Belmont winner A.P. Indy.

Judging post-Derby racing and stud records together, we conclude Seattle Slew enjoyed the best post-Derby career of any Kentucky Derby winner in history.