He served in the United States Army Air Forces during World War II era as a pilot.
After obtaining a degree in Music from the University of Alabama, he studied singing with Marie Sundelius at the New England Conservatory.
[2] Cox made his Italian debut at the Festival dei Due Mondi in Spoleto,[2] where he appeared as Rodolfo in La bohème.
He made his Covent Garden debut in October 1975, singing the title role in Siegfried.
Cox was married to the mezzo-soprano Anna Reynolds, whom he had met at Bayreuth and with whom he later ran a successful academy for aspiring singers.