He was the grandson of J. P. Morgan the financier, and great-great-grandson of Alexander Hamilton, the first Secretary of the Treasury of the United States.

[4] After graduation, Hamilton worked for a newspaper publisher, a Wall Street banking firm, and even tried his hand at producing motion pictures.

[6] Hamilton went on to serve as the Deputy Commissioner of the Department of Public Markets in New York City, earning a $1 a day,[6] until a disagreement with Mayor Fiorello LaGuardia forced his resignation.

Under his leadership, the group assisted in preserving Hamilton Grange, the historic summer house of his great-great-grandfather, and oversaw its transfer to the National Park Service.

[17] On December 26, 1935, the same day his divorce to his first wife was finalized in Reno, Nevada, he married the widow, Elizabeth Malcolm Peltz Warburton Wanamaker (1905–1988).