McCormack, John, 1884–1945, Irish-American tenor, b. Athlone, Ireland. He made his debut in London in 1907. In 1909, Oscar Hammerstein brought him to the United States. After his debut in New York City he sang with the Boston and Chicago opera companies but after 1914 sang principally in concert and for phonograph records. He was widely beloved for the singing of simple sentimental songs. He became a U.S. citizen in 1917. In 1938 he retired.