American opera singer. A baritone, he was a leading artist for many years with the Metropolitan Opera in Manhattan borough of New York City, New York.
Born to Russian Jewish immigrant parents, Warren was first employed in his father’s fur business. In 1935, he joined the chorus at Radio City Music Hall. In 1938, he entered the Metropolitan Opera Auditions of the Air. His natural gifts were apparent and he was immediately given a contract. The Met sent him to Italy that summer with a stipend to study.
Returning to America, Warren made his concert debut at the Metropolitan Opera in excerpts from La traviata and Pagliacci during a concert in New York City in November 1938. His formal operatic debut took place there in January 1939, when he sang Paolo in Simon Boccanegra. A recording contract with RCA Victor soon followed.
Warren later sang in San Francisco, Chicago, Mexico City, and Buenos Aires. He appeared at La Scala in Milan in 1953, and in 1958, he made a highly successful tour of the Soviet Union, but for most of his career he remained in New York City and sang at the Met. Sometime during that period, he converted to Roman Catholicism, the faith of his wife Agatha, and became extremely devout.
Although he sang Tonio in Pagliacci, Escamillo in Carmen, and Scarpia in Tosca, he was particularly acclaimed as one of the finest interpreters of the great Verdi baritone roles, above all the title role of Rigoletto, which was captured in 1950 in an RCA Victor recording with soprano Erna Berger and tenor Jan Peerce, conducted by Renato Cellini.
Warren took part in an historic television milestone in 1948, when he sang in the first-ever live telecast from the Metropolitan Opera. Giuseppe Verdi’s Otello was broadcast complete by ABC-TV on November 29, 1948, the opening night of the season. Warren sang the role of Iago.
In 1958 Warren toured the USSR. He was one of the few American artists allowed to do so and had great success at concerts in Leningrad and Kiev. The concerts were recorded and excerpts have been released on the RCA LP and later CD Leonard Warren: On Tour in Russia.
Warren’s last complete performance was in the title role of Simon Boccanegra on 1 March 1960 at the Met. Three days later, in a performance of La forza del destino with Renata Tebaldi, he died on stage at about 10:20 PM EST. The cause of death was determined to be a massive cerebral hemorrhage; Warren was only forty-eight years old.

Link to Wikipedia biography