Abraham Kingsley "King" Macomber (March 7, 1874 – October 6, 1955) was an American adventurer, businessman, philanthropist, Thoroughbred-racehorse owner and breeder.

He was born in Morristown, New Jersey, the second of the three sons of Henry Kirke Macomber, a medical doctor who moved his family to Pasadena, California, in 1883.

As a young man, in 1894 Kingsley Macomber explored parts of Central Africa at the invitation of American adventurer Frederick Russell Burnham.

[1] In 1905, Kingsley Macomber, Henry E. Huntington, and William R. Staats developed the Oak Knoll subdivision in terrain between Pasadena and San Marino, California.

After World War I, the Macombers made a chateau in France, at Carrières-sous-Poissy, their primary residence, and, in 1927, sold the Paicines ranch to Walter Murphy.

[2] From 1892 until her marriage to Kingsley Macomber, Myrtle Harkness had spent much time around horses at her father's Walnut Hall Farm near Lexington, Kentucky.

While the ban on wagering was lifted within two years, and racing returned to U.S. tracks, many owners retained large operations in Europe, and, by 1925, Macomber had more than one hundred horses in training in England.

Nonetheless, he supported California racing, and, in 1923, he became a founding member and director of the Pacific Coast Jockey Club, headed by Adolph B.

During the second decade of the 20th century, Kingsley Macomber was a frequent visitor to Europe and, around 1919, he purchased the Haras de Cheffreville horse breeding farm.