He also taught violin at the Juilliard School of Music for almost four decades and in 1968 founded the Usdan Center for the Creative and Performing Arts in Wheatley Heights, Long Island.
[7] In 1950 he returned to Philadelphia to create the role of Nika Magadoff in the world premiere of Gian Carlo Menotti's The Consul,[8] and continued with the production when it moved to Broadway later that year.
[11] That same year he was the tenor soloist in Hector Berlioz's Requiem with conductor Charles Munch and the Boston Symphony Orchestra at the Tanglewood Festival.
[14] He also sang in concert performances with the Baltimore Symphony Orchestra that year; including singing Prince Shuisky to the Boris of Jerome Hines and the title part in Berlioz's La damnation de Faust.
Menotti's story portrayed Kaspar as being hard of hearing and once joked that he had written it so because his brother "had always believed one of the kings was deaf since he never got all the presents he’d asked for".
[19] McKinley continued to play Kaspar, along with the other original adult cast members, for annual live television broadcasts up through 1964.
He sang in two more world premieres for the NBCOT; the roles of Anuchkin in Bohuslav Martinů's The Marriage (1953)[21] and "The Voice of the Letterbox" in Lukas Foss' Griffelkin (1955).
[22] Some of the other roles he filmed with the company included Captain Vere in Benjamin Britten's Billy Budd (1952),[23] Herodes in Richard Strauss' Salome (1954),[24] Monostatos in Wolfgang Amadeus Mozart's The Magic Flute (1956),[25] and Prince Shuisky in Modest Mussorgsky's Boris Godunov (1957).
That same year he founded the Suzanne and Nathaniel Usdan Center for the Creative and Performing Arts, a summer music camp in Wheatley Heights, Long Island.