A Hollywood Connection: Louis B. Mayer’s Influence at the Kentucky Derby

May 12, 2025 Jennifer Kelly / TwinSpires.com

Hollywood's glitzy and glamorous names of the 1930s and 1940s graced more than just the red carpets at movie premieres; they also could be found at racetracks like Santa Anita and Del Mar. Some even dabbled in owning a few equine athletes, leaving their mark on the sport through their efforts to bring together the right stallion and mare to create magic.

One of those Tinseltown titans who devoted time and money to the sport was studio executive Louis B. Mayer. His influence on racing, specifically his connections to multiple Kentucky Derby winners, remains a fascinating part of the Run for the Roses’ history.

Film Titan, Racing Rookie

As head of the Metro-Goldwyn-Mayer studio, Louis Burt Mayer knew a thing or two about stress. The former junk dealer turned entertainment magnate was behind the company that brought filmgoers a litany of classic films during Hollywood’s Golden Age in the 1930s, 1940s, and 1950s: The Wizard of Oz, Gone with the Wind, The Women, Singin’ in the Rain, and more. Famous for his star system and for developing child stars like Judy Garland, Mayer was traveling in Europe with another executive in 1937 when he saw a doctor who suggested “that while there was nothing organically wrong with him, he was rather tensed up and should relax more, possibly find a hobby,” according to a 1960 Sports Illustrated article.

The suggested hobby, of course, was “the breeding and racing of Thoroughbred horses,” and when similar advice was once given to Colonel E.R. Bradley, he founded Idle Hour Farm and would go on to own four Kentucky Derby winners. With the same aplomb that he applied to his business interests, Louis B. Mayer dove into racing.

Though the legendary film executive spent only about a decade in the sport, his 504-acre Mayer Stock Farm in Riverside County became a hub for California breeding, helping to revive a flailing pursuit in a state that had added Santa Anita Park, Hollywood Park, and Del Mar before the end of the 1930s. The Golden State’s racing scene was heating up, and Mayer wanted to be part of it; the end result of his investment saw this racing rookie influence the breeding of four Kentucky Derby winners.

If You Build It, They Will Run

When a $1 million bid for Man o’ War was met with a resounding no from Samuel Riddle, Mayer’s efforts to find a nice stallion to head up his new stud took him to Australia, where he picked up Beau Pere for $100,000 in 1941. His bid to buy the English stallion Hyperion was similarly unsuccessful. Still, he did come away with one of his sons, Alibhai, an unraced colt who went on to sire Kentucky Derby winner Determine and Your Host, who in turn produced the great Kelso.

With those two stallions at the helm, Mayer’s breeding program took off. When trainer Clyde Van Dusen came west to work for the MGM executive, he brought a mare named Betty Derr, winner of the Debutante Stakes and Latonia Oaks, with him. Mayer bought her from Van Dusen and mated her with War Admiral to produce the filly Iron Maiden. She would win the Del Mar Handicap for the MGM executive and then became a reine-de-course mare, producing 12 foals, of which 10 raced and seven were winners. Among her foals were Iron Liege, 1957 Kentucky Derby for Calumet Farm, and the mare Iron Reward, a Mayer’s Beau Pere daughter. Iron Reward did not win any of her eight starts but made up for it all with a colt named Swaps.

A son of English stakes winner Khaled, Swaps came east from California to Kentucky to beat Nashua in the 1955 Kentucky Derby, touching off a historic rivalry between the last great Belair-bred horse and the Golden State upstart with ties to Mayer’s breeding program. Swaps would set four world records at age four and then survive a career-ending leg fracture to sire horses like Chateaugay, 1960 Kentucky Derby winner; champion mare Primonetta; and Hall of Famer Affectionately.

Mayer’s purchase of Betty Derr from Van Dusen would also yield a second good producer in Judy-Rae, by Beau Pere. Her on-track career went nowhere, but her foals sealed her legacy. Judy Rullah, her daughter by Nasrullah, was a stakes winner at age two. Another daughter by Princequillo, the unraced Princess Matoaka, became the fifth granddam of Kentucky Derby and Preakness winner California Chrome. Nearly eight decades after Louis B. Mayer’s turn in racing, his influence still appears in the pedigrees of some of the sport’s biggest stars.

The End of an Era

A decade after he bought his first horse, Louis B. Mayer’s divorce from his first wife, Margaret, necessitated selling off his racing interests. Not only did he need the money for the settlement, but supposedly, his second wife, Lorena, was not as into the sport as he was. The dispersal sale at Santa Anita attracted 7,000 fans and grossed $1.5 million. He brought in $4.4 million more as he sold off the rest of his stock over the next few years.

Mayer returned to racing on a smaller scale in the 1950s and eventually bred the 1959 Preakness winner Royal Orbit. He bred the mare Honeymoon, great-granddam of Dahlia, the transatlantic superstar and Hall of Famer. In addition to breeding, Mayer also bought stars like Busher, the War Admiral filly he purchased for $50,000, who would win Horse of the Year in 1945 and join the Hall of Fame in 1964.

From Kelso to Chrome, the MGM executive was one of a plethora of Hollywood personalities who made a name for themselves in racing as well as in filmmaking. Like Bing Crosby and Mickey Rooney, Mayer enjoyed the racetrack as much as the movies and parlayed his investment in the sport into historic connections to its signature race, the Kentucky Derby.