His uncle joined the British Army at New York, and was appointed Commissary-General of Naval Prisoners in North America in the Autumn of 1779.

His brother William was appointed British Commissary of Naval Prisoners in the South, based in Charleston, where he died in 1781.

[2] Shortly after the end of the War, Robert was joined by James Lenox, his youngest brother who came from Scotland, and established the merchant house of Jas.

Together, they were the parents of twelve children, but only six, five girls and one boy, lived to maturity:[2] Lenox died at his residence, 59 Broadway in New York City on December 13, 1839.

Upon his death, he left a fortune of over one million dollars and 30 acres of land between Fourth and Fifth Avenues to his only son,[9] who by 1855 was the third richest man in New York.