 He has appeared in many of the world's well-known opera houses, including the Metropolitan Opera in New York City, the San Francisco Opera, Lyric Opera of Chicago, Houston Grand Opera, Seattle Opera, the Dallas Opera, the Opera Company of Philadelphia, the Pittsburgh Opera, The Santa Fe Opera, The Royal Opera in London, the Paris Opéra, the Bavarian State Opera in Munich, Theater an der Wien in Vienna, Opera Theatre of Saint Louis, Teatro Real in Madrid, and the Théâtre Royal de la Monnaie in Brussels.He has also appeared at the Glyndebourne Festival near London, the Ravinia Festival near Chicago, and the Mostly Mozart Festival in New York City.In 2011, Gunn was featured as a guest star in the Mormon Tabernacle Choir's annual Christmas concert before an audience of 80,000 in Salt Lake City.