His maternal grandfather was Baron John Cornelius van den Heuvel, the one-time governor of Dutch Guiana.

[8] After the Mexican War, he went to California and briefly interned for William Tecumseh Sherman Lucas, Turner & Co. bank before becoming[10] the administrator of the New Almaden quicksilver mine in Santa Clara County.

[3] Upon the outbreak of the Civil War, he left his crops and volunteered as a private in the Seventh Regiment, New York National Guard.

Toward the close of that campaign Hamilton was elevated to command the Right Wing of the Army of the Mississippi, consisting of the 3rd and 4th Divisions.

[16] On June 4, 1877, he delivered an address in front of the New York Historical Society, that was later published into a book, Our National Flag, the Stars and Stripes, Its History in a Century.

[6] In 1889, he wrote to The New York Times, calling for a return to civility and grace in allowing foreigners to compliment the United States and its leaders who have departed.

On July 11, 1886, several years after his first wife's death, he married Louisa Francis Paine Allen (1832–1898) at the Park Hotel in Manhattan.