Fleming was born in Panama Park in Duval County, Florida. He spent his early years with his parents, Lewis Fleming and his second wife Margaret Seton, on their St. Johns River plantation, "Hibernia". The plantation narrowly escaped destruction at the hands of the Independent Battalion, Massachusetts Cavalry in mid-April 1864 when Colonel Guy V. Henry, a relative of the Fleming family, ordered it spared. During the American Civil War, Fleming served the Confederate cause by enlisting as a private in the 2nd FloridaRegiment and received a battlefield promotion to first lieutenant, and subsequently to the rank of captain. After being wounded, Fleming returned to Florida and actively enlisted new volunteers, commanding a volunteer company at the Battle of Natural Bridge at St. Marks on March 6, 1865. By the end of the war, Fleming had served under four generals: John Magruder, Joseph Johnston, John Bell Hood, and Robert E. Lee. After the war, Francis Fleming studied law and was admitted to the bar in 1868, becoming a partner in the firm of Fleming and Daniel, later Fleming and Fleming. In 1871, he married Floride Lydia Pearson, the daughter of Florida Supreme Court justice Bird M. Pearson. Together the couple had three children: Francis Philip Jr., Elizabeth Fleming, and Charles Seton. Francis P. Fleming authored a book memorializing his brother, titled The Florida Troops/A Memoir of Captain C. Seton Fleming C.S.A., originally published by Times-Union Publishing House, Jacksonville, Florida, 1884. Its preface includes: "The preparation of the following pages was not commenced with the design of publication; but for the purpose of collecting and preserving in manuscript form, a brief memoir of one, in whose life was combined all the elements of true nobility, with that daring heroism which characterized his service as a soldier, during the most eventful period of this country's history, which I felt might be read with profit and pleasure by kindred of another generation." Original copies are quite rare. Fleming later entered politics, and became the fifteenth Governor of Florida on January 8, 1889, serving until January 3, 1893, the sole term provided by state law at that time. Notable events during Fleming's term include:
Francis P. Fleming was the son Lewis Fleming and his second wife, Margaret Seton. Fleming Island, Florida (an un-incorporated community in between Orange Park and Green Cove Springs in Clay County, Florida was part of the Fleming family's Spanish Land Grants. The area has since retained the name Fleming Island. The former governor and his wife, Floride, are buried in The Old City Cemetery, Jacksonville, Florida. University Athletic Field, the original football facility at the University of Florida, was renamed Fleming Field in 1915 at the urging of the late governor's son, Francis P. Fleming Jr., who served on the university's Board of Control, and was an alumnus of the class of 1922. The venue was replaced by much larger Florida Field in 1930, but the grassy area to the north of the current stadium is still known as Fleming Field.