[2] In 1884, Cannon was appointed Comptroller by President Chester A. Arthur to succeed John Jay Knox.

[3] Due to Cannon's efforts, the crisis was averted because the New York Clearing House Association quickly extended credit to threatened banks.

[8] After resigning from the government, Cannon moved to New York City and joined the National Bank of the Republic as vice-president where his predecessor Comptroller, John Jay Knox, served as president.

In 1915, Cannon donated Alessandro Longhi's Portrait of Count Carlo Aurelio Widman, the grandnephew of Pope Clement XIII, to the Metropolitan Museum of Art in New York.

[11][12] On November 20, 1879, Cannon was married to Jennie Olive Curtis (1851–1929),[13] the daughter of Gold Tompkins Curtis (1821–1862)[14] and relation of John Jay Knox, in Washington, D.C.[4] Her father was a prominent attorney who gave up his practice during the U.S. Civil War to raise a company, the 5th Minnesota Volunteers to fight, dying in 1862 during his service.

[1] Together, they were the parents of:[4] His wife, known for her forceful and talented speaking skills, was a prominent suffragist who advocated for the right to vote for women,[15] and in 1915 was the Delaware County Suffrage Leader,[16] providing the club with its headquarters.

[2] In 1900, Cannon purchased the Convent of San Michele alla Doccia sotto Fiesole in Florence, Italy.