Сергей Васильевич Рахманинов (Sergei Rachmaninoff)
He naturalized to American citizenship on February 1, 1943 (eight weeks before he died).
Sergei Vasilievich Rachmaninoff (Russian: Серге́й Васи́льевич Рахма́нинов; Russian pronunciation: [sʲɪrˈɡʲej rɐxˈmanʲɪnəf]; 1 April [O.S. 20 March] 1873 – 28 March 1943) was a Russian composer, pianist, and conductor. Rachmaninoff is widely considered as one of the finest pianists of his day and, as a composer, one of the last great representatives of Romanticism in Russian classical music.
Early influences of Tchaikovsky, Rimsky-Korsakov, and other Russian composers gave way to a personal style notable for its song-like melodicism, expressiveness and his use of rich orchestral colors. The piano is featured prominently in Rachmaninoff's compositional output, and through his own skills as a performer he explored the expressive possibilities of the instrument.