He and his younger twin sister Frances, who died young, were born on August 8, 1845, in Moravia, New York.

They were the youngest children of con artist William Avery "Bill" Rockefeller and Eliza Davison.

In September 1861, while still underage, he joined the 7th Ohio Infantry and participated as an infantryman in the battles of Winchester, Port Republic, Cedar Mountain, Chancellorsville, Gettysburg, Lookout Mountain, and other battles including Sherman's march to Atlanta.

[1] He held various jobs in Cleveland, eventually becoming involved in his brothers' Standard Oil Co. Frank became one of the principal promoters of the company, and later served as its vice president.

The 8,000-acre ranch stood on a large tract of cheap land in Belvidere, Kansas, west of Wichita (originally spotted by his father on his travels).

Eventually the Atchison, Topeka and Santa Fe Railroad brought in fresh settlers shrinking the free range for cattlemen.