Born in Odessa in Ukraine, Moiseiwitsch studied at the Imperial Adademy of Music there and won the Anton Rubinstein Prize when he was just nine years old. He later took lessons from Theodor Leschetizky in Vienna. He first appeared in London in 1909, and later settled in England and took British nationality. His American debut was in 1919.
Moiseiwitsch was particularly noted for his interpretations of the late Romantic repertoire, especially the work of Sergei Rachmaninov (who was an admirer of his playing).