William George McCloskey (10 November 1823 – 17 September 1909) was an American Catholic prelate who served as Bishop of Louisville from 1868 to 1909.

[3] After his ordination, the archdiocese assigned McCloskey as assistant pastor at Church of the Nativity in Manhattan, serving with his brother George.

[2] After ten months at Nativity, William McCloskey in 1853 requested a transfer back to Mount St. Mary out of desire to live in a cloister.

[2] In 1857, McCloskey succeeded Reverend William Henry Elder as director of St. Mary's Seminary, where he taught moral theology and sacred scripture.

1868, by Cardinal Karl-August von Reisach, with Archbishops Xavier de Mérode and Salvatore Nobili Vitelleschi serving as co-consecrators.

[4] In that same year, Bishop McCloskey was instrumental in bringing the Sisters of Mercy to Louisville in October 1869, where they took over operation of the U.S. Marine Hospital in that city.

McCloskey died on September 17, 1909, at Preston Park Seminary at Bellarmine College in Louisville.