[4] The Union Club was founded in 1836 at a meeting held at the home of John McCrackan at 1 Bond Street, and was considered "the most thoroughly aristocratic private institution in the city.

During the Civil War, the club refused to expel its Confederate members, despite taking a strong line on suppressing anti-draft riots.

[10] The Knickerbocker Club was founded by members of the Union who thought the membership standards have fallen.

[11] In 1918, the Union began using women waitresses to free male employees for service related to World War I.

[4] By the 1950s, urban social club membership was dwindling, in large part because of the movement of wealthy families to the suburbs.

Founder of The Independent, an anti-slavery religious weekly started in 1848, manager of The New Englander (later re-named the Yale Review), president of the American Union Commission, member of the committee to create the New York Metropolitan Museum of Art, gave the eulogy at President Lincoln’s funeral and at the Union Club [13] and assisted the Treaty of Berlin with the religious liberty clause.

More than 300 members of the Union Club joined the U.S. military services during World War II.