World-renowned opera star Simon Estes has perform­ed for queens and popes, U.S. presidents and Hollywood celebrities. He’s sung in famous opera houses around the globe and danced with Nelson Mandela at the World Cup ceremonies in South Africa.

Now Estes’ bass-baritone voice is echoing from within small-town school auditoriums and theaters across Iowa, where he is greeted with standing ovations by enthusiastic local music-lovers.

For the past three...