According to the Vienna State Opera, where he held the honorary title of Kammers‹nger, King died in the United States. He was 80. Born in Dodge City, Kansas, King studied at Louisiana State University and Kansas City University. Originally a baritone, he switched to tenor in the late 1950s and made his debut at San Francisco Opera as Don Jos_ in Carmen opposite Marilyn Horne in 1961; the same year he appeared as Cavaradossi in Tosca in Florence.

King was a member of the Deutche Oper Berlin's ensemble from 1962 to 1965. He debuted at Salzburg in 1962, at the Vienna State Opera in 1963, at the Bayreuth Festival in 1965, and at the Metropolitan Opera in 1966. He was also heard at the Paris Opera, the Royal Opera, La Scala, and elsewhere.

He sang such Wagnerian roles as Lohengrin, Siegmund, and Parsifal, as well as Florestan in Fidelio, the Emperor in Strauss's Frau ohne Schatten, and Manrico in Il trovatore.

King taught at the Indiana University School of Music.