Born in Saviano, province of Naples, Simonelli was educated at the Normal School of Naples and, at first, he worked as a bank clerk in that city. In 1897, on the ship Oregon, he sailed from Naples, Italy and, on February 10, arrived in New York City. Here he began to teach Italian Language. In 1898-99, he worked as a librarian at St. Xavier College, New York City. In 1899, under Comm. Joseph N. Francolini, Mr. Simonelli started his banking career as a clerk with the Italian Savings Bank of New York City. The following year he was appointed secretary of the bank and in 1901, trustee. In 1902, he became a U.S. citizen and joined the Republican Party.
In 1903, Simonelli was instrumental in securing the services of Enrico Caruso for the New York Metropolitan Opera. Throughout his life, he continued to engage other famous opera singers, such as Maria Barrientos, Beniamino Gigli, Titta Ruffo, Riccardo Stracciari, and others for the New YorkMetropolitan Opera. Simonelli married Rosa in 1903 and had two children: Julius and Maria. From 1920 to 1932, Mr. Simonelli was President of the Italian Savings Bank. The King of Italy, Victor Emmanuel III, conferred upon him the honour of Commander of the Order of the Crown of Italy. From 1922 to 1930, Simonelli was Treasurer and Director of the Italian Chamber of Commerce and Treasurer of the Italian Hospital of New York City. During those years he was also vice president of the Comitato pro Sacco and Vanzetti. In 1926, he was Director and organizer of the Seward National Bank. From 1927 to 1934, he was also Director of the Italian Super-Power Co. When, in 1932, the Italian Savings Bank and the East River Bank merged, giving birth to a new Institution named East River Savings Bank in New York City, Simonelli was appointed Vice-President and Trustee of this Bank with his Office at 225 Lafayette Street. He resided in New York City at 326 W. 89th St. until 1936. In 1937 Simonelli retired to Italy, at his castle “Villa Simonelli” in San Paolo Belsito, Naples. There, he spent the rest of his life as a country gentleman. He died in 1960. His remains rest in the Simonelli family mausoleum in the cemetery of Sant'Erasmo in Saviano, Naples.
