Delafield was born at his father's residence, 16 Wall Street in New York City, on November 18, 1802,[1] and named after Rufus King, the first U.S.

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

[14] After an education in New York, Delafield engaged in "mercantile business" and served as an officer of the Phenix Bank from 1823 to 1835, and actuary and secretary of the Farmers' Loan and Trust Company (which later became Citibank) from 1835 to 1852.

[17] Delafield & Baxter, which was headquartered at 54 Pine Street,[18] produced Rosendale cement and their mill was driven by water-power and consisted of "three crackers, and four run of four and half feet stone" and three quarries.

[22] Together, they were the parents of seven children:[23] Like his father and brothers, Delafield established a country seat for himself, Rufus' being in New Brighton, Staten Island, where he brought the residence "to the highest state of cultivation.

"[1] Today, the former Delafield estate in the Livingston neighborhood, is home to the Staten Island Cricket Club.