Leo Sirota began studying piano at the age of five. By the age of nine he was already giving concerts and came to the attention of Paderewski, who invited the boy to study with him. Sirota's parents, however, felt he was too young, and so he attended the conservatories in Kiev and, later, Saint Petersburg. However, in 1904 he went to Vienna to study with Ferruccio Busoni.
He worked as rehearsal pianist with the conductor Jascha Horenstein, whose sister, Augustine Horenstein, he married. Sirota's Vienna debut concert must have been a memorable occasion: it comprised the Mozart sonata for two pianos with Busoni playing the other piano, followed by the Busoni Piano Concerto, with Busoni conducting, and ended with the two piano version of the Liszt Don Juan Fantasy.
Sirota and his family settled in Japan in 1929, staying there for 16 years, teaching and giving recitals. He was a piano teacher of Minoru Matsuya (1910–1995) and Takahiro Sonoda (1928-2004). While in Japan, he championed Yamaha pianos against the prevailing fashion in Japan for Bechstein and Steinway instruments.
During World War II, he and his wife were interned in Karuizawa, Nagano, while his daughter was safe in the United States. After the Second World War he moved to America and taught in St. Louis. A local radio station frequently asked him to broadcast, and much of his surviving recorded output comes from the paper-based tapes that the studio gave to him after each broadcast. His repertoire was vast, including the complete works of Chopin, which he broadcast. His playing is characterised by a luminous tone and unfussy, almost fastidious interpretations, underpinned by an astonishing technique - his rendition of Rosenthal's arrangement of Chopin's minute waltz with the right hand in thirds was said to have astounded Arthur Rubinstein. Because his recorded legacy required specialised remastering, it is only recently that his stature as a pianist has been appreciated.
Sirota died in 1965.
His daughter was Beate Sirota Gordon.