Descendant of a brother of Governor Edward Winslow, and Mayflower passenger Mary Chilton, John Winslow entered the U. S. Navy in 1827, and after service during the Mexican War was promoted to commander in 1855. Although born in the South, Winslow, with his New England heritage and strong anti-slavery sentiments, joined the Union navy, and was assigned to the Western River Squadron.
In 1863 he took command of the Kearsarge, then in the Azores, and patrolled the continental coast in search of Confederate ships sailing to Europe for repairs. Through intelligence, he learned of the docking of the notorious Alabama, "a most troublesome enemy," at Cherbourg. Upon her re-launching, Winslow sailed to neutral territory and engaged the Confederate ship June 19, 1864, sinking her and taking seventy prisoners. He and his crew were hailed throughout the United States and in Congress upon their return; Winslow was promoted to commodore effective the date of the battle. He retired a rear-admiral in 1870 after commanding the Pacific Fleet.
Winslow is picture on the deck of the Kearsarge looking out to sea. Couper has followed the format of the companion relief of Thomas G. Stevenson by Bela Pratt, at its side, with a lively naturalism. After attending Cooper Union, the sculptor had spent two decades in Florence, Italy studying and working with local and American sculptors, notably Daniel Chester French (Joseph Hooker, Thomas Bartlett) and Thomas Ball (John Andrew), whose studio he joined until his return to New York in 1897.