By the age of six, Scalero was under the tutelage of Pietro Bertazzi, a violinist, musical instrument maker and instructor at the Conservatorio St. Cecilia in Torino. In 1881, Scalero entered the Liceo Musicale di Torino under Luigi Avalle. At the age of 15, Scalero came under the tutelage of César Thomson. Scalero appears to have returned to his home at Moncalieri for a time for health reasons, before returning to Torino (Turin) to study with Camillo Sivori through 1889, appearing during this time with the Sivorni Quartet.
In 1891, Scaleri made his debut as a recitalist in Leipzig, following which he performed in Milan, Rome, London, and throughout Europe to critical acclaim. In 1895, Scaleri went to London to study and assist violinist August Wilhelmj (concert master of the world premiere of Wagner's Ring of the Nibelungs in Bayreuth). In 1900 he left London for Vienna, where he became a composition student of Eusebius Mandyczewski.
1907 returned Scalero to Rome. Here he joined in 1913 the Società del Quartetto and became its musical director and first violinist. In 1919, he was succeeded by Ernest Bloch as a composition teacher at the Mannes School of Music in New York. After 1927, he taught at the famous Curtis Institute of Music in Philadelphia, while apparently keeping a residence in Gressoney. One of his most successful students at Curtis was composer Samuel Barber. In 1946 he returned to Montestrutto in Ivrea, Italy, where he died in 1954.
- A Suite for String Quartet and String Orchestra
- La Divina Foresta, symphonic poem for large orchestra
- Violin Sonata (Op.12, D minor, published 1910)
Pupils of Rosario Scalero
- Samuel Barber (1910-1981)
- Gian Carlo Menotti (1911-2007)
- Nino Rota (1911-1979)
- Milton Adolphus (1913-1988)
- Luigi Zaninelli (1932- )
- Lukas Foss (1922-2009)
- Roland Leich (1911-1995)
- Ned Rorem (b. 1923)
- Leonard Gregory Kastle
- Muriel Hodge
- David Barnett
- Carl Bricken
- George Rochberg (1918-2005) 
- Rolf C. Scheurer (1918 - 2006)
- George Walker (1922- )
- Hugo Weisgall (1912-1997)
- The Strad. October 1895. Unknown parameter
- Kenneson, Claude (1998). Musical prodigies. ISBN 1-57467-046-8.
- Donal Henahan (January 24, 1981). "Samuel Barber, Composer, Dead: Twice Winner of Pulitzer Prize". The New York Times.
-  Grace Notes: Lukas Foss
- Anderson, E. Ruth (1982). Contemporary American Composers, 2nd ed., pp. 434-435. G. K. Hall, Boston. ISBN 0-8161-8223-X.
- "German Wikipedia entry on Scalero" (in German). Retrieved 25 August 2010.
- Music Is My Faith - An Autobiography. David Mannes, ISBN 1-4067-3935-9