[1] He was the son of Thomas Hillhouse (1766–1835) and Anna Van Schaick Ten Broeck (1787–1865), who married in 1812 in Hudson, New York.

[5] After ten years as a country gentleman farmer, and at the urging of his father-in-law, Hillhouse became involved in politics and the anti-slavery movement.

Due to his work as chairman, he was appointed Adjutant General of New York by Governor Edwin D. Morgan, from July 1861 until the end of 1862.

[1] After the war ended, he returned to Geneva to resume the life of a private citizen, however, he was quickly elected in 1865 on the Republican ticket as New York State Comptroller, serving from 1866 to 1867,[6] but defeated for re-election in 1867.

"[1] He was in office for eleven years and three terms until he resigned in 1881 to become first President of the Metropolitan Trust Company in New York City,[7] a position he held until his death in 1897.