It's made all the more amazing by the fact that he had no formal musical training when he set out to become a singer.
The 38-year-old Miller was a bruising fullback out of the University of Colorado who never quite made it to the National Football League.
He started out by singing along to operas at home, then landed a part at a musical festival in Michigan. He then underwent formal training and got hired for the Metropolitan Opera production of Puccini's "Madame Butterfly" in 2006.
He has now sung with operas around the world. This season, he'll appear at the Met in Verdi's "Un Ballo in Maschera."
It opens Nov. 8.
(Copyright 2012 The Associated Press. All rights reserved.)