In 1824, Gouverneur was elected as a People's Party (faction of the
Democratic-Republican party) member of the
New York State Assembly, serving in the
48th New York State Legislature in 1825. He was aligned with
Assembly Speaker Clarkson Crolius, also from
New York County. On November 19, 1828, he was appointed
Postmaster of New York City, succeeding former
U.S. Representative and
Senator Theodorus Bailey who died in office on September 6, 1828. While in New York he invested in racehorses, and the
Bowery Theatre along with
James Alexander Hamilton, son of
Alexander Hamilton, and Prosper M. Wetmore. Gouverneur was executor of Monroe's estate, which had to be sold off to pay the debts. Monroe was buried in the Gouverneur family vault at the
New York City Marble Cemetery, until descendants had the remains moved to the
James Monroe Tomb in the
Hollywood Cemetery in
Richmond, Virginia. A ceremony was held at the Gouverneur vault 175 years later, on July 8, 2006. Monroe's personal papers were left to Gouverneur, who also was asked to support his wife's sister
Eliza Monroe Hay (also his cousin, then a widow). Gouverneur started work on publishing the papers or a book on Monroe, but it was never finished. After Mrs. Hay died in 1840, the Gouverneurs moved to
Washington, DC where he worked in the consular bureau of the
U.S. Department of State from 1844 to 1849. After Congress agreed to buy the papers of
President Madison, Gouverneur proposed a similar arrangement, which was concluded in 1850. Some personal papers would be retained for a few generations. ==Personal life==