[8] His father was a Scottish-American merchant and banker with Maitland & Kennedy who served as president of the Saint Andrew's Society of the State of New York.

His maternal uncle was bibliophile and philanthropist James Lenox, from whom Kennedy inherited a portion of his estate.

He was one of the organizers of the Union League Club and, during the U.S. Civil War he was a "strong Unionist and Republican, though he afterward took no part in politics.

Kennedy had previously donated Mihály Munkácsy's 1878 historical genre picture The Blind Milton Dictating Paradise Lost to his Daughters (which he bought from art dealer Charles Sedelmeyer) to the Library in 1879.

[9] On his return voyage following a four-month sojourn to Europe in hopes of improving his health, Kennedy died aboard the Norddeutscher Lloyd steamship Trave on September 14, 1887.

[19] In 1889, his personal library which included many rare works like "Aldine first editions of the classics, incunables, vellum manuscripts, historical and beautiful bindings, Americana, and other rarities" was sold at the Fifth-Avenue Art Galleries.