He prepared the choruses for legendary conductor Arturo Toscanini in
the early 1940s, after which choral conductor Robert Shaw took over the
job.
One of the pre-eminent choral directors in the United States, he is
most famous for the choral arrangement and American lyrics for the
Ukrainian Christmas song, 'Carol of the Bells'.
His "Carol of the Bells" employs the melody of a Ukrainian song called "Shchedryk". The original song is actually about springtime, not Christmas or bells.
He attended the Russian Cathedral Choir School in New York, along with his siblings. He studied at Juilliard and later taught there.
His family immigrated to the US from what was then the Austro-Hungarian Empire and is today part of northeastern Slovakia.