He fought key legal battles that opened American culture to 20th century art movements, including his Congressional appeals to overturn the Payne–Aldrich Tariff Act.

His paternal grandparents, James, a blacksmith, and Mary (née Madigan) Quinn, natives of County Limerick, had settled in Tiffin in 1851.

As the second decade of the 20th century began, his interests shifted across the English Channel to works by Manet, Camille Pissarro, and Pierre Puvis de Chavannes.

According to author Richard Spence, Quinn was a supporter of the Irish nationalist cause and associated with figures such as John Devoy and Roger Casement, although he had reportedly worked for British Intelligence services before, during, and after World War I.

[5] In the early 1920s Quinn represented Margaret Anderson and Jane Heap for their publication in The Little Review of serial portions of James Joyce's Ulysses, which the U.S. Post Office had found "obscene".

Rediscovery of The Waste Land manuscript was announced in conjunction with the publication of Benjamin Lawrence Reid's biography, The Man from New York: John Quinn and His Friends in 1968.

A huge and controversial event, the 1913 Armory Show (officially The International Exhibition of Modern Art) in New York City included examples of Symbolism, Impressionism, Post-Impressionism, Neo-Impressionism, and Cubism.

The event included works by Henri Matisse, André Derain, Maurice de Vlaminck, Robert Delaunay, Jacques Villon, Albert Gleizes, Jean Metzinger, Gino Severini, Marie Laurencin, Constantin Brâncuși, and Raymond Duchamp-Villon, in addition to American artists Arthur B. Davies, Walt Kuhn, Marsden Hartley, Stanton Macdonald-Wright, and Max Weber.