At the time of his birth, his father was serving as President of New York and Erie Railroad and later became a U.S. Representative from New Jersey.

[6] His maternal grandfather was Archibald Gracie, a Scottish-born shipping magnate and early American businessman and merchant in New York City and Virginia.

[7] After graduating from Harvard, he took lessons in engineering from Professor Mahan at West Point before joining his father's banking house, James G. King's Sons, in 1854.

[7] He began as a clerk, eventually became a partner in the bank and then withdrew in 1861 to found his own brokerage business, having been a member of the New York Stock Exchange (of which he served as president in 1872).

[7] Together, they were the parents of one child, a son:[7] After a two-week illness, King died in New York City on November 18, 1908.