Francis was appointed to the staff of Bellevue Hospital (1874), and to the chair of pathology and practice of medicine in the College of Physicians and Surgeons (1875–82).

Francis' brother Augustus Floyd Delafield travelled extensively around Scotland and brought back a set of golf clubs in 1880s.

He landed in New York City on April 5, 1783, and found himself especially welcomed as the bearer of a manuscript copy of the text of the treaty of peace, which had been handed him at the moment of sailing by an official in the British service.

The conditions of peace were known, but the text had not yet been made public in England; and, although the official copy had been forwarded, the "Vigilant" had outstripped the bearer of the government dispatches by some days.

He was one of forty gentlemen who subscribed $10,000 each, and founded (February 1, 1796) the United insurance company, also acting as a director, and serving as president for many years.

His summer residence on the East River, opposite Blackwell's Island, known as" Sunswick," built in 1791, was one of the largest and best appointed private houses near New York.

Francis Delafield was fitted for college in private schools in New York City, and at Yale received a dissertation appointment in junior year and was a member of Phi Beta Kappa.

In 1863, he graduated from the College of Physicians and Surgeons at Columbia, and then for some months continued his medical studies abroad — in Paris, Berlin and London.

Upon his return to the U.S. in 1865, he became surgeon in the New York Eye and Ear Infirmary, and physician and pathologist in 1871 to the Roosevelt Hospital (now Mount Sinai West).

He had served also as pathologist and attending physician to Roosevelt Hospital and as surgeon to the New York Eye and Ear Infirmary.

[1] Francis Delafield was the primary physician who was consulted following the shooting of United States President William McKinley in September 1901.

While Francis argued to use the X-Ray machine to photograph McKinley's organs and assess the damage, he met opposition from others unwilling to use the new technology.

She had two children from her first marriage to the architect Robert Spurgeon; And two children from her second marriage to the attorney Frank A. Zunino Jr. Francis Delafield was of the family of Count de la Feld, which dates back to the darkest period of the Middle Ages (about the sixth century) and seated at the Chateaux of La Feld, in Alsace (extensive ruins still remain).

Because of his service in Hastings during the 1066 invasion of England, Hubertus De La Feld received large grants of land from William the Conqueror and settled near Halifax.

In England, the family rose in stature when John Delafield distinguished himself in the imperial service against the Turks: having taken a standard from the enemy at the Battle of Zenta in Hungary was in 1697 created a Count of the Holy Roman Empire by Emperor Leopold I.