Thomas Stewart was an American bass-baritone who specialized in Wagnerian roles.
Thomas James Stewart was born in San Saba, Texas. He graduated from Baylor University in 1953 and then went to the Juilliard School, where he studied with Mack Harrell. He made his debut in 1954 as La Roche in the American premiere of Richard Strauss's Capriccio, and went on to sing with the New York City Opera and the Lyric Opera of Chicago.
He married soprano Evelyn Lear in 1955, and the following year the couple participated in a studio cast recording of Kurt Weill's Johnny Johnson, first produced in 1936. They traveled to Berlin in 1957 on Fulbright Scholarships. He made his major-role debut with Städische Opera, now the Deutsche Oper Berlin, in 1958 as Escamillo in Bizet's Carmen. He created the role of Jupiter in Giselher Klebe's 1961 opera Alkmene and remained on the Berlin company's roster until 1964. He debuted at the Royal Opera House in 1960, again as Escamillo, and sang frequently at Covent Garden, with roles including Don Giovanni, the title role in The Flying Dutchman, and Gunther in Götterdämmerung) until 1978; he was a regular at the Bayreuth Festival for 12 years, singing the majority of Wagner's heroic baritone roles, including Wotan/Wanderer and Gunther in the Ring Cycle, the Dutchman, Wolfram in Tannhäuser and Amfortas in Parsifal.