[4] Like his near-contemporaries Henry E. Huntington and J.P. Morgan, Stetson was also a noted book collector:[10] his collection was the subject of an article in The New York Times in 1935.

[12] In 1934,[13] he deposited a copy of Arsène Houssaye's Des destinées de l'ame, bound in human skin, at Harvard's Houghton Library.

In the aftermath of World War I, he adjudged Marshal Józef Piłsudski's government as good for America, in economic terms; and American business was more than happy to respond to the Polish need for capital and investment.

[24] In 1981, alongside Hugh S. Gibson and Anthony Joseph Drexel Biddle Jr., Stetson was considered perhaps one of the few diplomats to have "understood and sympathized with Poland's strategic dilemma" during that time.

[26] They had two daughters[2] and two sons: Stuart Carlisle, a Marine Corps officer killed in a plane crash in 1941;[8] and John B. Stetson III, a National Guardsman who also predeceased his father, in 1944.