Vernon was born in Memphis in 1953; he received his undergraduate degree in voice from the University of Memphis. He was a finalist in the Metropolitan Opera National Council auditions in 1977 and a member of the Houston Grand Opera studio from 1977 _79.
He made his Met debut in 1981 as one of the animals in the company's premiere of Ravel's L'Enfant et les sortilges. Regular roles at the house included Count Ceprano in Rigoletto, the Jailer and Sciarrone in Tosca, and Jago in Verdi's Ernani. He also sang in Schoenberg's Moses und Aron in 1999, Busoni's Doktor Faust in 2001, Prokofiev's The Gambler in 2001, the same composer's War and Peace in 2002 and Wolf-Ferrari's Sly in 2002.
Vernon made his San Francisco Opera debut in 1985, as Prince de Bouillon in Cilea's Adriana Lecouvreur. He appeared with the Houston Grand Opera, the Washington Opera, San Diego Opera, Cincinnati Opera and other U.S. companies in roles including Pimen in Boris Godunov, Colline in La Bohme, Banquo in Macbeth, Ferrando in Il trovatore, and the Commendatore in Don Giovanni.
He died at his home in Shohola, Pennsylvania, according to Opera News. No cause of death was reported.